THE PRESIDENT’S OFFICE MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

COMPETENCY BASED SECONDARY EXAMINATION SERIES

PHYSICS                                                                        FORM             THREE

TIME: 3 HOURS                                                                             NOVEMBER 2022

Instruction

1. This paper consists of section A, B and C with a total of eleven [11] marks
2. Answer all questions in section A and B and two [2] questions from section C
3. Mathematical table and non – programmable calculator may be used
4. Cellular phones are not allowed in the examination room
5. Write your Examination number on every page of your answer sheet provided
6. Where necessary the following constants may be used

• Acceleration due to gravity g = 10mls²
• Density of water, p= 1000 kg /m³or 1g/cm³

SECTION A [15 MARKS]

1. For each of the items [i] – [x] choose the correct among the given alternatives and write its letter beside the item number in the answer sheets provided.

1. Which one among of the following is a factor on which up thrust exerted on a body by fluid depends:

1. Volume of the fluid B. Mass of the fluid C. Viscosity of the fluid D. Density of the fluid E. Temperature of the fluid

2. A layer of colour less water is carefully floated in a cylinder on top of blue copper sulphate solution after a time, the water becomes blue, because of?

1. Liquid friction B. Density changes C. Diffusion

4. Viscosity E. Pressure changes

3. If the mass of copper over the volume of copper is 8.9g/cm³. Find the volume 89g of copper

1. 10 ^-5 cm C. 10^-5m³
2. 0.1 cm³D. 100CM³E. 10cm³

4. Aluminum is used in making motor engines, pistons and cylinders due to

1. Its low density and high conductivity
2. Low density and maximum pressure
3. High density and varying mass
4. Its high conductivity and high density
5. Its heavy weight and low conductivity

5. The acceleration of a moving body may be found from;

1. The area under its velocity-time graph.
2. The slope of the velocity-time graph.
3. The area under its distance-time graph.
4. The slope of the distance-time graph.
5. The slope of the peak of its distance-time graph

6. Oil is used as a lubricant in a machine because it has

1. Low density
2. High viscosity
3. Low pressure
4. High pressure
5. Low viscosity

7. When light is totally internally reflected from the boundary of a certain transparent material and air the critical angle is found to be 50⁰ the speed of light in the material is

1. 2.1 x 10⁸m/s
2. 2.2 x 10⁸m/s
3. 1.94 x 10⁸m/s

D.2.3 x 10⁸m/s

E. 3.0 x 10⁸m/s

8. Why buildings are constructed with wide foundation?

1. Because of power
2. In order to reduce pressure exerted by the building on the ground
3. So as to build large house
4. To increase pressure of the ground so as to maintain holding the house.
5. To avoid earth quake

9. The energy from the hot rocks within the earth is called.

1. Tidal energy
2. Water energy
3. Cool- burning energy
4. Biomass energy
5. Geothermal energy

10. A reference was a certain device to judge football game in 90 minutes at MKAPA arena, that device was:-

1. Football C. Stop watch
2. Tape measure D. 90 Minutes E. Line man

Section B [60 marks]

Answer all questions

3. [a]. By using well labeled diagram, explain in short why the stem of the hydrometer is made thin and weighted with mercury or lead shorts? [06 marks]

[b]. A ship is made of steel and it is expected that it should sink in water. However it does not sink. At the same time a coin once dropped in water it will sink. How can you solve this contradiction so as to help a form one student who is totally confused? [04 marks]

4. [a]. It has been found the efficiency of a pulley system is always less than 100%. Giving two reasons explain the secret behind. [04 marks]

[b]. A meter rule is pivoted at its mid-point. If two objects of weigh 1.0N and 2.0N are suspended at 30cm and 90cm respectively from one end, calculate the position

5. [a]. State the laws of refraction of light

[b]. The diagram below shows a ray of light incident on a glass prism at an angle.

Complete the diagram to show as it emerges from the other side [05marks]

[c]. Sketch a ray diagram to show the formation of a solar ellipse [03marks]

6. [a]. Give one difference and one similarity between a fuse and a circuit – breaker [04 marks]

[b]. A cell supplies a current of 0.6A through a 2Ω coil and a current of 0.2Athrough a752Ω coil. Calculate the e.m.f and internal resistance of the cell [06marks]

7. [a]. Explain on the basic of conservation of linear momentum, how a fish propels itself forward by swishing its tail back and forth [04 marks]

[b]. A block and tackle system of 5 pulley is used to raise of 490N steadily through a is then 1800 J. calculate the efficiency of the system and efforts applied[06 marks]

8. (a) Explain four (4) factors affecting resistance of a conductor. (6 marks)

     (b) Describe two (2) defects of simple cell(4 marks)

Section C [25 marks]

Answer two [2] question form this section

9. When a simple pendulum displaced at a small angle swings to and fro, in this motion potential energy and kinetic energy changes by alternating each other. With the aid of diagram verify the alternation of these energies.(8.5 marks)

(b) A 50kg girl runs up a staircase of 50 steps each step is 15cm in height in 5s. Find Work doneagainst gravity by the girl and Power she use to run(4 marks)

10. (a) A drum at station A is connected to a wire string at station B. A man at A beats the drum while another person at B places his ear at the wire and hears two sounds separated by the time interval of 0.5 seconds. If the velocity of sound in the wire string is 5280m/s. How far apart are the two men. (5 marks)

(b) How long will it take a 240V, 3000W electric immersion heater to raise the temperature of 150 litres of water in a well lagged copper tank of mass 20kg from 15℃ to 70℃. Also find the cost at 5 shillings per kwh. (5 marks)

11. (a).A plane mirror and concave mirror both they produce an image from the given object. Draw the diagram to represent the formation of image in each case (for the concave mirror consider an object to be at the center of curvature, (C). Hence show two similarities and two differences of images formed. ( 6 marks)

(b) Explain the formation of mirage (4 marks)

THE PRESIDENT’S OFFICE

REGIONAL ADMINISTRATIVE AND LOCAL GOVERNMENT

FORM THREE EXAMINATIONS SEPT 2022

NEW NECTA FORMAT

PHYSICS

PHYSICS FORM THREE

Where necessary use the following constants

Acceleration due to gravity (g) = 10m/s²

Density of water = 1g/cm³/ 1000kg/m³

ATTEMPT ALL QUESTIONS IN THIS SECTION

1. (a)For each of the items (i) – (x) choose the correct answer among the given alternatives and write its letter beside the item number.

1. A force F newton’s gives a mass of 2kg an acceleration of 4m/s². A force of 3F newton will give a mass of 8kg an acceleration in m/s² of?

1. 1
2. 3
3. 6
4. 12
5. 24

2. A Uniform beam XY is pivoted at one end X and a vertically upward force of 4N at Y keeps the beam horizontal. The weight of the beam in Newton’s is

1. 8
2. 6
3. 4
4. 2
5. 1

3. In the process of charging by induction in static electricity

1. A conducter is rubbed with an insulator
2. A charge is produced by friction
3. Negative and positive charges are separated
4. A positive charge induces a positive charge
5. Electrons are sprayed into an object.

4. In a single rope 4-pulley system, the mechanical advantage is less than 4 because

1. The effort may vary
2. The load is raised
3. The upper pulleys do not move
4. Friction acts on the pulleys
5. The weight of the pulleys may be neglected

5. Which of the following are non-renewable energy sources

1. Wave energy
2. Biofuels
3. Fossil fuels
4. Radiant energy
5. Geothermal

6. An airship is floating stationary high above the ground in this case

1. Up thrust = airship weight
2. Air temperature inside the ship = Air temperature outside the ship
3. Air density outside the ship is greater than air density inside
4. Air density outside the ship is less than air density inside the ship
5. The air up thrust is greater, than the air weight

7. Which of the following describe the particles in a sold at room temperature

1. Close together and vibrate
2. Close together and moving around at random
3. For apart and moving at random
4. Close together and stationary
5. Far apart and stationary

8. The relationship between the local length (f) and radius of conture of a concave mirror (r)is that

1. f=2r
2. f =r
3. 
4. 

9. When two cars A and B are morap in the same direction; the velocity of A relative to B is given by

1. V_AB=V_A – V_B
2. V_{AB =} V_AB – V_A
3. V_AB = V_A + V_B
4. None of the above

10. The following work on the principle of total internal reflection except

1. Prism Pens copes
2. fibre optic cable
3. mirage
4. mirror pens cope

2. Match the items in List A with a response in List B by writing the letter of the correct response beside the item number

SECTION B (60 MARKS)

ATTEMPT ALL QUESTIONS IN THIS SECTION

3. (a)With the aid of a ray diagram, explain why a concave mirror is used as a shaving mirror

(b)A convex mirror of focal length 15cm is used to produce an image an object placed 20cm from the pole of the mirror 

Find the position and nature of the image formed

4. (a)How is absolute velocity different from Relative velocity

(b)A bird is plying at 80/km/hr. due East relative to the air. A wind is blowing at 30km/hr in the north East direction as seen from the ground. What is the velocity of the bird relative to the observer on the ground? 

(c) Identify three ways of reducing friction force acting on a body

5. (a)Explain why it is not possible for you to push a car when you are seated inside it

(b)A uniform beam of mass 50kg and length 6m is supported by two vertical strings at A and B such that each pant is 0.5m from each end A mass of 40kg is also hung at m from A. Find the tension in the strings at points A and B

6. (a)(i)Draw a well labelled diagram of a hydrometer

(ii) Explain the important of the following on a hydrometer 

1. Narrow stem
2. Wide bulb

(b) A cube of side 10cm and mass 400g floats in water

1. What fraction of the cube is under the water
2. What is the extra force that must be exerted on the cube such that it is completely submerged in the water

7. (a)With a clear diagram show how a prism can be used to produce a spectrum when white light falls on its

(b)A compound microscope has objective lens of focal length 8cm and eyepiece lens of focal length 4cm the distance between the lenses is 28cm. the lens is adjusted such that the final image is at infinity

1. Calculate the position of the object from the objective lens
2. What is the angular magnification of the lens

8. (a)Explain the importance of anomalous expansion of water to marine organision

(b)A wheel and exle has wheel radius of 20cm and axle radius of 5cm. The efficiency of the machine is 90%

1. What is the velocity of the machine
2. What is the effort required to raise a load of 2000N

SECTION C

ATTEMPT ANY TWO QUESTIONS IN THIS SECTION

9. (a)Explain why during the installation of electrical wires that transmit electricity from one place to another the wires are left sagging and not tight

(b)The figure below shows a bimetallic strip having two metals invar and brass. (Brass has a higher linear expansitivity than invar)

Explain how the bar will bend if it is heated to a higher temperature than room temperature

(c) A telegraph wire has a length of 30m and is made of metal of linear expansitivity 0.00002/K

Find the change in length from a hot day temperature 30°C to a very cold day - 5°C

10. (a)What are the laws that govern friction force

(b)Explain why coefficient of Kinetic friction is always smaller than coefficient of state friction 

(c)Three forces act on a body as shown below

Find the value of T and F

11. (a)Explain the appearance of a  blue shirt with red spots when viewed through

1. Blue light
2. Red light
3. Green light

(b)Convex mirrors are always used as driving mirrors. With the aid of a diagram explain why these kinds of mirrors are used in this case 

(c)What is the maximum magnification produced by a convex lens of local length 5cm.

THE PRESIDENT’S OFFICE

MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

COMPETENCE BASED SECONDARY EXAMINATION SERIES

PHYSICS TERMINAL EXAMINATION

FORM THREE-2022

INSTRUCTIONS

1.   This paper consists of sections A, B and C with a total of eleven (11)  questions.
2.    Answer all questions in sections A and B and two (2) questions  from section C.
3.    Cellular phones and any unauthorised materials are not allowed in  the examination room.
4.    Non-programmable calculators may be used.
5.    Write your Examination Number on every page of your answer  booklet(s).
6.   Where necessary the following constants may be used:

1.                       Acceleration due to gravity, g = 10 m/s ²
2.                      Density of water = I .0 g/cm ³ 
3.                      Pie= 3.14.
4.                       Coefficient of linear expansivity of the brick 1.2 x 10 ^-5 K ^-1
5.                       Speed of light in air = 3 x 10⁸ m/s. 
6.                      Speed of sound in air = 340 m/s.

SECTION A (15 Marks)

Answer all questions in this section.

1. For each of the items (i) - (x), choose the correct answer from among the given alternatives and write its letter beside the item number in the answer booklet provided.

1.              Measurement of mass by using equal ­arm beam balance uses the principle of

1.             conservation of momentum.
2.             conservation of energy
3.             moments
4.             gravitational pull of the earth
5.              conservation of matter.

2.           The principle of fluid pressure which is used in hydraulic brakes, is the

1.             pressure is the same at all levels in a fluid B
2.             increases of pressure are transmitted equally to all parts of a fluid
3.              the pressure at a point in fluid is due to the weight of the fluid above it
4.             increases of pressure can only be transmitted through fluids
5.               the pressure at a given depth is proportional to the depth in the fluid.

3.         The surface tension of a fluid is due to

1.             molecules on its surface
2.             a semi­permeable membrane which covers it
3.             the Brownian motion of surface molecules
4.             the cohesive force between its surface molecules
5.              the adhesive force between molecules of different materials

4.         Given cubical expansivities of mercury and glass are 1.8 x 10 ­4 /K and 1.0 x 10 ­5 /K respectively; a glass vessel of capacity 100ml holding mercury to the brim, heated through 100°C will expel mercury of the following volume.

1.             18ml
2.              28ml
3.             10ml
4.              8ml
5.              17ml.

5.            A rod of insulating material is charged positively by rubbing against a piece of fabric and the latter is tested for electric charge. The fabric will be expected to have a

1.             positive charge equal to that on the rod
2.             positive charge less than that on the rod
3.              negative charge equal to that on the rod
4.             negative charge greater than that on the rod
5.              negative charge less than that on the rod.

6.         A gearwheel X is used to turn another gearwheel Y. X has 15 teeth and Y has 5 teeth. When Y makes 6 revolutions X has made

1.             A 6 revolutions
2.              2 revolutions
3.             3 revolutions
4.             5 revolutions
5.               18 revolutions.

7.       A material which allows some light to pass through it but one cannot see through it is said to be

1.             transparent
2.             translucent
3.              luminous
4.             opaque
5.              colorless.

8.    The positive pole of a dry cell is made of

1.             carbon rod
2.             zinc can
3.             ammonium chloride
4.              copper rod
5.               manganese dioxide.

9.         Each scientific instrument is limited in accuracy. What is the shortest length that can be accurately recorded or measured by a metre rule?

1.             0.02 mm
2.             0.2 mm
3.              0.2 cm
4.              0.02 cm
5.               0.2 m.

10.            A body weighs 10 N in air and 8 N when completely immersed in water. Neglecting upthrust in air, its weight in a liquid of density 1.5 g/cm 3 will be;

1.             3 N
2.              18 N
3.             10 N
4.             2 N
5.              7 N

11.         When a person perspires on a hot day

1.             A evaporation occurs and helps to cool the body
2.             heat is conducted away from the body
3.             latent heat keeps the body warm
4.              the body is insulated from the warm air
5.              condensation occurs and helps to cool the body.

2. Match the items in list A with the responses in list B by writing the letter of the correct response

beside the item number.

SECTION B (60 Marks)

Answer all questions in this section.

3. (a) (i) Explain the pressure of a gas in terms of the kinetic theory of gases. (2 marks)

(ii) How is diffusion explained by the kinetic theory of gases? (2 marks)

(b) (i) State Charles’s Law. (1 mark)

(ii) Sketch the graph of volume against temperature for a perfect gas.(2 marks)

(c) (i) What is the absolute zero of temperature?(1 mark)

(ii) 150 cm 3 of dry gas at 30°C was heated until its volume became 450 cm 3 . What was the final temperature?

4. (a ) (i) Name, draw and mention one use of the three different types of diverging lenses?

(b) Where should an object be placed such that its image as formed by a converging lens will be

(i) at infinity (ii) of the same size (iii) erect?

(c) A nail 6.0 cm long is placed 15 cm away from a convex lens of focal length 10.0 cm. The nail

is stuck perpendicular to the optical axis of the lens. Determine the positions and height of the nail

5. (a ) Explain the terms potential energy and kinetic energy giving one example of each.

(b) A pendulum bob of mass 50g is pulled aside to a vertical height 20 cm from the horizontal and then

released. Find

(i) the maximum potential energy of the bob

(ii) the maximum speed of the bob

(c) (i) Suppose the length of the thread of the pendulum in discussion was 1.0 m, what could its periodic time of oscillation be?

(ii) State the principle applied by the pendulum experiment.

6.(a) A cricket ball of mass 180g bowled with a velocity of 20m/s is hit back towards the bowler at a velocity of 15m/s. The impact lasts for 0.4s. Calculate

1.              The impulse,
2.           Force applied on the ball

(b). A car of mass 1000kg travelling at 36km/h is brought to rest by applying brakes. Calculate the distance travelled by the car before coming to rest, if the frictional force between the wheels and the road is 2 000N

(c) An effort of 250N raises a load of 900N through a distance of 5m. If the effort moves through 25m, calculate 

1.              The work done in raising the load,
2.           The work done by the effort,
3.         The efficiency of the machine.

7. Give scientific reasons for the following statements

1. If a mercury thermometer with a ‘thick’ glass bulb is dipped into hot water, the mercury level first drops slightly and then rises quickly in the bore.
2. Steel bridges are usually supported by rollers
3. The telephone cables “sag” in warm weather and tighten in cold weather
4. The mouth of a glass bottle is gently heated when the glass stopper is rigidly stuck to the mouth so as to remove it.
5. A sealed plastic bottle filled with water to the brim breaks after some time if it is placed in the freezing compartment of a refrigerator.

8. Explain the following statements

1. Electric kettles and geysers have the heating coils at the bottom
2. In a room, the windows are at a lower level and the ventilators at a higher level
3. During the day cold air flows from the sea to land
4. The bottom of cooking vessels are usually blackened
5. A metal knob of a wooden door fees much colder than the door
6. Electric metal kettles are fitted with wooden or plastic handles
7. People wear woollen garments in cold weather to keep their bodies warm.

9. (a) The extension produced in a spiral spring is 6cm when a mass of 300g is attached to it. Calculate the spring constant of the spring 

(b) When a body of mass 400g is completely immersed in a liquid, the upthrust on the body is 1.4N. Find the weight of the body in the liquid.

SECTION C (10 Marks)

Answer one (1) question from this section.

10. (a) State Pascal’s principle of transmission of pressure. (01)

(b) A piston of small cross section area of 30.0 cm 2 is used in hydraulic press to exert a force

of 300.0N on the enclosed liquid. A connecting pipe leads to a large piston of cross

section area 600.0 cm 2 . Find

(i) the force sustained by the larger piston (03)

(ii) the force applied on the smaller piston to support 2.0 tonnes on the larger piston.

(03)

(iii) the mechanical advantage (MA) of the pistons of the press. (02)

11. (a) What is meant by magnetic materials? Give two examples.

(b) State the law of magnets.

(c) Explain with an illustration how one can locate the position of a north-pole of a bar magnet.

(d) Explain with an illustration how to magnetize a steel bar using an electric current.

THE PRESIDENT'S OFFICE

MINISTRY OF REGIONAL GOVERNMENT AND LOCAL GOVERNMENT

MID TERM-1 EXAMINATION

PHYSICS FORM-3

2022- MARCH/APRIL

TIME: 2:30 HRS

Instructions

1.   This paper consists of sections A, B and C with a total of eleven (11)  questions.
2.    Answer all questions in sections A and B and two (2) questions  from section C.
3.    Cellular phones and any unauthorised materials are not allowed in  the examination room.
4.    Non-programmable calculators may be used.
5.    Write your Examination Number on every page of your answer  booklet(s).
6.   Where necessary the following constants may be used:

1.  Acceleration due to gravity, g = 10 m/s ²
2. Density of water = I .0 g/cm³
3. Pie= 3.14.
4.  Coefficient of linear expansivity of the brick 1.2 x 10 ^-5K ^-1
5.  Speed of light in air = 3 x 10⁸ m/s. 
6. Speed of sound in air = 340 m/s.

SECTION A (15 Marks)

Answer all questions in this section.

1. For each of the items (i) - (x), choose the correct answer from among the given alternatives and write its letter beside the item number in the answer booklet provided.

(i) Which pairs of instruments would you use to correctly measure the diameter of a small ball bearing?

1.  Measuring tape and vernier caliper
2.  Slide rule and micrometer screw gauge
3.  Vernier caliper and slide rule
4.  Micrometer screw gauge and vernier caliper
5. Metre rule and micrometer screw gauge

(ii)Which one is a characteristic of a plane mirror?

1. It forms image which is real and opaque.
2. It forms an image which is larger than the object.
3. It forms an image which is real and laterally inverted
4. It forms an image which has the same size as the object.
5. It forms an image which is smaller in size than the object.

(iii) The correct arrangement of metals in ascending order of their linear expansivities is?

1. Iron, Copper, Invar, Brass and Nickel
2. Nickel, Brass, Invar, Copper and Iron
3. Brass, Copper, Nickel, Iron and Invar
4. Invar, Iron, Nickel, Copper and Brass.
5. Nickel, Brass, Iron, Invar and Copper.

(iv) Which of the following is the correct weight of a body of mass 48 g when placed on the moon surface?

1.  0.48 N 
2.  4.8 N
3.  0.80 N
4.  0.048 N
5.  80.0 N. 

(v)The correct formula to find the elastic force constant (k) of a spring is

1. Tension/extension
2. mass/extension
3. extension/mass
4. extension/tension
5. tension/mass

(vi) Why is oil used as a lubricant?

1. It has low density.
2. It is highly viscous.
3. It is flammable.
4. it is inflammable    
5. It is less viscous. 

(vii) A bar of copper is heated from 293 K to 333 K. Identify a false statement among the following:

1. Its density will increase slightly
2. Its length will increase slightly
3. Its electrical conduction will decrease slightly
4. Its mass will not change
5. Its weight will remain unchanged.

(viii) Which among the following is not a property of magnetic lines of force due to a bar magnet?

1. They have a direction from North Pole to South pole outside the magnet
2. They do not exist inside the magnet
3. They have a direction from South pole to North pole inside the magnet
4. They tend to be close inside the magnet but are wider apart outside the magnet 
5. They form complete loops.

(ix) When an object moves around a horizontal circle of centre O with a constant speed, its acceleration will be

1. zero
2. towards the centre
3. away from the centre
4. along the tangent to the circle
5. along the direction of rotation.

(x) Which statement about a wet-and-dry bulb hygrometer is correct?

1. Wet bulb thermometers measure the temperature of the surrounding air.
2. The temperature recorded by a wet-bulb thermometer is always larger than that recorded by a dry-bulb thermometer.
3. When the difference in temperature recorded by wet and dry-bulbs is larger no water evaporates.
4. The value of relative humidity is low when the temperature of wet and dry bulbs is the same.
5. Wet-bulb is cooled by the process of evaporation of water.

2. Match the items in List A with responses in List B by writing the letter of the correct response beside the item number in the answer booklet provided.

SECTION B (60 Marks)

Answer all questions in this section.

3. (a) Write down the second and third equations of motion in a straight line.

(b) Explain the following terms as they are applied in motion in a straight line:

(c)A stone is thrown vertically upwards with an initial velocity of 50 m/s.

(i) Calculate the time that the stone will take to return back to the thrower.

(ii) What will be the maximum height reached?

4. Three resistors of 2 Ω, 4 Ω   and 6 Ω   are connected in series to a battery of e.m.r 24 V and have negligible internal resistance.

(a) Draw the circuit diagram including the battery, ammeter, switch and the three resistors.

(b) Find the current flowing in the circuit drawn in 4 (a) above.

(c) Find the potential difference at the ends of each resistor in 4 (a).

5. (a) (i) What is meant by the term thermal expansion?

      (ii) Mention two applications of thermal expansion of solids.

(b)    (i) List three areas where bimetallic strips are used.

  (ii) Why a bimetal strip made of brass and invar is curved outside with brass?

(c)    Describe how simple fire alarm system operates.

6.  (a) State Pascal’s principle of pressure 

 
(b)  What are the three factors that affect the liquid pressure?

(c)  Calculate the area of an object if the pressure exerted is 0.2 N/m² and its force is 2 N.

7.  (a) What are the uses of the following devices?

(i)  Manometer 

(ii)  Hare’s apparatus (inverted U-tube)

(iii)  U-tube 

(iv)  Barometer 

(b) Why a big Elephant manages to walk comfortably in muddy soil without sinking while a human being may sink easily?

8.  (a) Mention three uses of current electricity

(b) Why is it advised to connect bulbs in parallel arrangement during installation of electricity in most buildings?

SECTION C (25 Marks)

Answer two (2) questions from this section

9.(a) State two conditions for a body to be in equilibrium.

(b) Distinguish between centre of mass and centre of gravity.

(c) A uniform metre rule AB is balanced horizontally on a knife edge placed 5cm from B with a mass of 60g at B. Find the mass of the ruler.

10.(a) Define the following terms as applied in Physics:

(i)Machine

(ii)Load

(b) Why is efficiency of machine less than 100%? Explain briefly.

(c) Simple machine was used to raise a load of weight 4000 N through a height of 0.8 m using an effort of 800 N. If the distance moved by effort was 4.8 m, calculate the: (i) Mechanical advantage. (ii) Velocity ratio.

11. (a) (i) Distinguish between primary and secondary cells, giving one example of each.

(ii) Identify two defects of a simple cell.

(b) (i) Explain why lead – acid accumulators are used in car batteries rather than dry cells?

(ii) A cell of unknown e.m.f, E and internal resistance 2? is connected to a 5? resistance. If the terminal p.d, V is 1.0V. Calculate the e.m.f, E of a cell.

THE PRESIDENT’S OFFICE

MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

SECONDARY EXAMINATION SERIES

   ANNUAL   EXAMINATION

FORM THREE-NOVEMBER 2021 

PHYSICS 1

Instructions

l. This paper consists of sections A, B and C with a total of eleven (11) questions.

2.  Answer all questions in sections A and B and two (2) questions from section C.

3.  Section A carries fifteen (15) marks, section B sixty (60) marks and section C carries twenty five (25) marks.

4.  Cellular phones and any unauthorised materials are not allowed in the examination room.

5.  Non-Programmable calculators may be used.

6.  Write your Examination Number on every page of your answer booklet(s).

1. Where necessary the following constants may be used:

(i)Acceleration due to gravity, g = 10 m/s² or 10 N/kg

(ii)Specific heat capacity of mercury is 1395 J/kg°C

(iii) 1g of water is equivalent to 1 cm³ 

(iv)    Pi = 3.14.            

SECTION A (30 Marks)

Answer all questions in this section.

1. For each of the items (i) - (x), choose the correct answer among the given alternatives and write its letter besides the item number in the answer booklet provided.

(i)The correct formula to find the elastic force constant (k) of a spring is

1. Tension/extension
2. mass/extension
3. extension/mass
4. extension/tension
5. tension/mass

(ii) Why is oil used as a lubricant?

1. It has low density.
2. It is highly viscous.
3. It is flammable.
4. it is inflammable    
5. It is less viscous. 

(iii)Which one is a characteristic of a plane mirror?

1. It forms image which is real and opaque.
2. It forms an image which is larger than the object.
3. It forms an image which is real and laterally inverted
4. It forms an image which has the same size as the object.
5. It forms an image which is smaller in size than the object.

(iv) In a light experiment, the results showed that less light was transmitted and the image was distorted. Which type of material was used?

1. A translucent material
2. An opaque material
3. A luminous material 
4. A transparent material
5. A non-luminous material

 (v)  What quantity of heat is required to raise the temperature of 25 kg sample of mercury from 20°C to 30°C?

1. 1,743,750J
2. 348,750J
3. 345,750J
4. 413,750J
5. 1,550,750J

(vi) Why is Mercury preferred in clinical thermometers as a thermometric of a liquid to water and alcohol?

1. It is denser than other liquids.
2. It is opaque and does not need colouring.
3. It is more sensitive to temperature.
4. It is active and does not wet the glass. 
5. It is a poor conductor of heat.

 (vii) Which of the following is an example of a scalar quantity?

1. Electric current 
2. Force
3. Velocity
4. Displacement
5. Acceleration

(viii)What role does the iris play in the human eye?

1. To hold the lens in position.
2. To prevent internal reflection.
3. To control the size of the pupil.
4. To control the thickness of the lens.
5. To protect the eye from light.

(ix) A launderer was thinking about a proper day for washing and drying clothes. Which day would he prefer most among the following?

1. Dry day 
2. Hot day 
3. Windy day
4. Still day 
5. Cold day

 (x) What will be the resistivity of a wire 2 metres long with a cross-sectional area of 0.50 mm² and a resistance of 2.20Ω 

1.  5.5 x 10^-7 Ωm 
2.  6.5 xlO^-7Ωm 
3. 2.3 x 10^-7 Ωm 
4.  1.1 x 10-⁶Ωm
5.  5.5 x 10^-6Ωm.

2. Match the items in List A with responses in List B by writing the letter of the correct response beside the item number in the answer booklet provided.

SECTION B (60 Marks)

Answer all questions in this section.

3. (a) Briefly explain why hydrometer 

(i) is weighed with lead shots.

 (ii) has a narrow stem.

(b)    A piece of rubber of volume 100 cm³    and the density of 0.45 g/cm³ floats in water. Calculate:

(i) The volume of rubber that partially immersed in water.

(ii) The force required to immerse the rubber completely.

4.       (a) List four factors which affect the rate of evaporation of liquids.

(b)    (i)  Define relative humidity.

(ii)  Calculate the relative humidity given that the reading on dry bulb hydrometer is 24°C and the wet bulb temperature reading is 16°C.

(c)    With the aid of a sketched graph, explain how temperature affects the saturated vapour pressure of water.

5. (a) Briefly explain why hydrometer 

(i) is weighed with lead shots.

 (ii) has a narrow stem.

 (b)    A piece of rubber of volume 100 cm³    and the density of 0.45 g/cm³ floats in water. Calculate:

(i) The volume of rubber that partially immersed in water.

(ii) The force required to immerse the rubber completely.

6. (a) How does the increase of length and cross-section area of a conductor affect its resistance?

(b) (i) State the function of a circuit breaker in a wiring system.

(ii) Determine the ratio of resistance of wire A to that of wire B which are made up of the same material such that wire A has half the length and twice the diameter of wire B.

7. (a) Give two examples which illustrate the rectilinear propagation of light.

(b) (i) The refractive index of light passing from water to air is 3/4. Calculate the critical angle. (ii) Outline two differences between primary and secondary rainbows.

(c)    In Figure 1, identify the names of colours labeled A, B, C, D, E, F and G.

11. (a) Mention two practical examples in our daily life in which the principle of conservation of energy is applied.

(b)(i) What is a simple pendulum.

(ii) Describe the energy changes that take place when a simple pendulum swings from one side to another.

(c)Name a machine or an apparatus used to change the following forms of energy.

1. Heat energy to mechanical energy.
2. Mechanical energy to electrical energy.
3. Electrical energy to sound energy.
4. Sound energy to electrical energy.
5. Heat energy to electrical energy.

SECTION C (25 Marks)

Answer two (2) questions from this section

9. (a) State the following rules: 

(i)  Cork screw rule.

 (ii)       Dynamo rule.

(b)    (i) Give one structural difference between A.C. and D.C. generators. 

(ii)      Mention one application of induction coil.

(c)    Figure 2 shows a transformer used to step down power. Assuming that there are no power losses, what will be the ammeter reading on the output part?

10. (a) (i) What is meant by the term thermal expansion?

      (ii) Mention two applications of thermal expansion of solids.

(b)    (i) List three areas where bimetallic strips are used.

  (ii) Why a bimetal strip made of brass and invar is curved outside with brass?

(c)    Describe how simple fire alarm system operates.

11.(a) (i) What are sustainable energy sources?

(ii) State four applications of energy generated from water.

(b)(i) Define geothermal energy.

(ii)Briefly explain how geothermal energy can be harnessed.

(c)(i) What is a windmill?

(ii)Mention three disadvantages of energy caused by wind. (iii) Does wind itself possess energy? Explain.

THE PRESIDENT'S OFFICE

MINISTRY OF REGIONAL GOVERNMENT AND LOCAL GOVERNMENT

MID TERM EXAMINATION

PHYSICSFORM-3

2021- AUG/SEPT

TIME: 2:30 HRS

Instructions

1.   This paper consists of sections A, B and C with a total of eleven (11)  questions.
2.    Answer all questions in sections A and B and two (2) questions  from section C.
3.    Cellular phones and any unauthorised materials are not allowed in  the examination room.
4.    Non-programmable calculators may be used.
5.    Write your Examination Number on every page of your answer  booklet(s).
6.   Where necessary the following constants may be used:

1.  Acceleration due to gravity, g = 10 m/s ²
2. Density of water = I .0 g/cm³
3. Pie= 3.14.
4.  Coefficient of linear expansivity of the brick 1.2 x 10 ^-5K ^-1
5.  Speed of light in air = 3 x 10⁸ m/s. 
6. Speed of sound in air = 340 m/s.

SECTION A (15 Marks)

Answer all questions in this section.

1. For each of the items (i) - (x), choose the correct answer from among the given alternatives and write its letter beside the item number in the answer booklet provided.

(i) A bar of copper is heated from 293 K to 333 K. Identify a false statement among the following:

1. Its density will increase slightly
2. Its length will increase slightly
3. Its electrical conduction will decrease slightly
4. Its mass will not change
5. Its weight will remain unchanged.

(ii) Which among the following is not a property of magnetic lines of force due to a bar magnet?

1. They have a direction from North Pole to South pole outside the magnet
2. They do not exist inside the magnet
3. They have a direction from South pole to North pole inside the magnet
4. They tend to be close inside the magnet but are wider apart outside the magnet 
5. They form complete loops.

(iii) When an object moves around a horizontal circle of centre O with a constant speed, its acceleration will be

1. zero
2. towards the centre
3. away from the centre
4. along the tangent to the circle
5. along the direction of rotation.

(iv) The image formed by plane mirrors are always

1. real, magnified and laterally inverted
2. virtual, laterally inverted and same in size
3. magnified, virtual and erect
4. laterally inverted, same in size and real
5. erect, real and magnified.

(v) The battery in the circuit shown in the following diagram has an e.m.f. of 2 V and negligible internal resistance.

What will be the current flowing in the 6 ? resistor?

1.  0.15 A
2. 0.64 A
3. 1.42 A
4. 0.10 A
5. 0.33 A

(vi) A body is said to be in equilibrium IF

1. it moves with uniform speed
2. the net force acting on it is zero
3. the upward and downward forces are equal
4. its centre of gravity is low positioned
5. its centre of gravity is high.

(vii) Tow forces of 5 N and 8 N are acting at the same point and are inclined at an angle of 45° to each other. What will be their resultant force?

1. 11.2 N
2. 12 N
3. 22.4
4. 1.2 N
5. 1.12 N

(viii) A solid metal cube has each side doubled to make a solid cube of the same metal eight times bigger in volume. The ration of resistivity of the new cube to resistivity of the old cube is

1.  8:1
2.  6:1
3.  1:1
4.  1:6
5.  1:8 

(ix) A green card with red flowers when viewed in a red light will appear:

1.  completely red
2.  completely yellow
3.  completely green 
4.  yellow with red flowers 
5.  green with red flowers. 

(x) Colours are produced when white light passes through glass prism because

1.  light waves interfere
2.  glass prism colours the light
3.  in glass different colours travel at different speeds
4.  different colours are filtered
5.  diffraction of light occurs.

2. Match the following items.

SECTION B (60 Marks)

Answer all questions in this section.

3. (a) In a light experiment, a narrow beam of light directed onto a glass prism leaves the prism and falls on a white screen. Draw a labelled diagram to show the experimental set-up and observation seen on a screen. 

 (b)     Explain two ways in which lens cameras differ from human eye.

4. (a) Briefly explain why hydrometer 

(i) is weighed with lead shots.

 (ii) has a narrow stem.

(b)    A piece of rubber of volume 100 cm³    and the density of 0.45 g/cm³ floats in water. Calculate:

(i) The volume of rubber that partially immersed in water.

(ii) The force required to immerse the rubber completely.

5.       (a) List four factors which affect the rate of evaporation of liquids.

(b)    (i)  Define relative humidity.

(ii)  Calculate the relative humidity given that the reading on dry bulb hydrometer is 24°C and the wet bulb temperature reading is 16°C.

6. (a) (i) What peculiar property does the effort has in all classes of levers?

(ii) A metre rule of weight 1.0 N is supported horizontally on two knife edges each placed 10.0 cm from its ends. If the weight of 1.5 N is placed at its mid-point, calculate the reaction at the supports.

(b) (i) State the law of floatation.

(ii) Find the fraction of the cork that partially immersed when a piece of cork of density 0.25 g/cm³and a mass of 20 g floats in water.

7. (a) Write down the second and third equations of motion in a straight line.

(b) Explain the following terms as they are applied in motion in a straight line:

1. Velocity.
2. Retardation.

(c)A stone is thrown vertically upwards with an initial velocity of 50 m/s.

(i) Calculate the time that the stone will take to return back to the thrower.

(ii) What will be the maximum height reached?

8. Three resistors of 2 Ω, 4 Ω   and 6 Ω   are connected in series to a battery of e.m.r 24 V and have negligible internal resistance.

(a) Draw the circuit diagram including the battery, ammeter, switch and the three resistors.

(b) Find the current flowing in the circuit drawn in 8 (a) above.

(c) Find the potential difference at the ends of each resistor in 8 (a).

SECTION C (25 Marks)

Answer two (2) questions from this section

9. (a) A beaker containing ice is heated from -5°C to 0°C and then from 0°C to 15°C. With the aid of a diagram, explain the variation of density with temperature. 

(b) A brick at 20°C has a dimension of 30 cm, 18 cm and 10 cm for length, width and height respectively. If a brick is heated to a new temperature of 150°C, calculate the new dimensions.

10.(a) State two conditions for a body to be in equilibrium.

(b) Distinguish between centre of mass and centre of gravity.

(c) A uniform metre rule AB is balanced horizontally on a knife edge placed 5cm from B with a mass of 60g at B. Find the mass of the ruler.

11. (a) Define the word coulomb.

(b) States Ohms law.

(c) Two resistors of 30 and 60 are connected in parallel to a 3V battery.

(i)Draw the schematic diagram.

(ii)Find the effective resistance of the circuit.

(iii)Calculate the current passing through the 60 resistor.

THE PRESIDENT'S OFFICE

MINISTRY OF REGIONAL GOVERNMENT AND LOCAL GOVERNMENT

AUGUST-SEPTEMBER   EXAMINATION SERIES

PHYSICS  FORM-3

2020

TIME: 2:30 HRS

Instructions

1. This paper consists of sections A, B and C with a total of eleven (11)          questions.
2.  Answer all questions in sections A and B and two (2) questions     from section C.
3.  Cellular phones and any unauthorised materials are not allowed in          the examination room.
4.  Non-programmable calculators may be used.
5.  Write your Examination Number on every page of your answer     booklet(s).
6. Where necessary the following constants may be used:
7.  Acceleration due to gravity, g = 10 m/s ²
8. Density of water = I .0 g/cm ³ 
9. Pie= 3.14.
10.  Coefficient of linear expansivity of the brick 1.2 x 10 ^-5 K ^-1
11.  Speed of light in air = 3 x 10⁸ m/s. 
12. Speed of sound in air = 340 m/s.

SECTION A (15 Marks)

Answer all questions in this section.

1. For each of the items (i) - (x), choose the correct answer from among the given alternatives and write its letter beside the item number in the answer booklet provided.

(i) Which pairs of instruments would you use to correctly measure the diameter of a small ball bearing?

1.  Measuring tape and vernier caliper
2.  Slide rule and micrometer screw gauge
3.  Vernier caliper and slide rule
4.  Micrometer screw gauge and vernier caliper
5. Metre rule and micrometer screw gauge

(ii) When the sun shines on the dark-coloured driving wheel of a car, the wheel feels warm. Why?

1.  It is because the sun warms the car by induction.
2.  It is because the sun gives energy to the wheel by convection.
3.  It is because the sun radiates thermal energy to the wheel.
4.  It is because the sun radiates heat to the glass windows.
5. It is because the sun conducts thermal •energy to the wheel.

(iii)Which one is a characteristic of a plane mirror?

1. It forms image which is real and opaque.
2. It forms an image which is larger than the object.
3. It forms an image which is real and laterally inverted
4. It forms an image which has the same size as the object.
5. It forms an image which is smaller in size than the object.

(iv)What role does the iris play in the human eye?

1. To hold the lens in position.
2. To prevent internal reflection.
3. To control the size of the pupil.
4. To control the thickness of the lens.
5. To protect the eye from light.

(v) The correct arrangement of metals in ascending order of their linear expansivities is?

1. Iron, Copper, Invar, Brass and Nickel
2. Nickel, Brass, Invar, Copper and Iron
3. Brass, Copper, Nickel, Iron and Invar
4. Invar, Iron, Nickel, Copper and Brass.
5. Nickel, Brass, Iron, Invar and Copper.

(vi) The suspended magnetic needle always comes to rest with its axis in a vertical plane called?

1. Geographic meridian
2. Magnetic meridian
3. Geographic declination
4. Magnetic declination
5. Geographic North Pole.

(vii) Which of the following is the correct weight of a body of mass 48 g when placed on the moon surface?

1.  0.48 N 
2.  4.8 N
3.  0.80 N
4.  0.048 N
5.  80.0 N. 

(viii) A car moving at steady speed has a frictional force on its surface whose size depends on its

1.  speed and surface area
2.  speed
3.  surface area
4.  weight 
5.  wheels speed. 

(ix) The image formed by plane mirrors are always

1. real, magnified and laterally inverted
2. virtual, laterally inverted and same in size
3. magnified, virtual and erect
4. laterally inverted, same in size and real
5. erect, real and magnified.

(x)Lenz’s law can be applied to predict the

1. magnitude of back e.m.f. in a circuit
2. magnitude of induced current in a circuit
3. direction of applied e.m.f. across the circuit 
4. direction of induced e.m.f. in a circuit 
5. direction of the applied e.m.f. within a circuit.

2. Match the items in List A with responses in List B by writing the letter of the correct response beside the item number in the answer booklet provided.

SECTION B (60 Marks)

Answer all questions in this section.

3. (a) Why a bubble of air increases in volume as it rises from the bottom of a pond of water to the surface? Briefly explain.

(b) A half meter rule AB is freely pivoted at 18 cm from end A and balances horizontally when a body of mass 35 g is hung 48 cm from end B. Calculate the mass of the rule. 

4. (a) Briefly explain why hydrometer 

(i) is weighed with lead shots.

 (ii) has a narrow stem.

(b)    A piece of rubber of volume 100 cm³    and the density of 0.45 g/cm³ floats in water. Calculate:

(i) The volume of rubber that partially immersed in water.

(ii) The force required to immerse the rubber completely.

5. (a) Give two examples which illustrate the rectilinear propagation of light.

(b) (i) The refractive index of light passing from water to air is 3/4. Calculate the critical angle. (ii) Outline two differences between primary and secondary rainbows.

6. (a) (i) What is the essential of kinetic theory of matter?

(ii) Sketch a graph showing how force applied in a stretched string varies with its extension.

(b) (i) State Hooke’s law.

(ii) List two applications of gamma rays.

7. (a) (i) Define turning effect of force and give its SI unit.

(ii) How the moment of force can be increased considerably in practical life? Give two examples.

(b) (i) List two factors that affect stability of a body

(ii) Briefly explain why the handle of a door is near its outside edge?

8. (a) (i) Distinguish between light spectrum and dispersion of light.

(ii) Briefly describe how a light ray passes through an equilateral glass prism.

(b) Study Figure 1 which represents three primary colours combines together and answer the questions that follow.

1. Identify the colours represented by the letters A, B, C and D.
2. What general name is given to the colours obtained by mixing two primary colours?
3. Name the colour produced as a result of mixing three primary colours.

SECTION C (25 Marks) 

Answer two ( 2) question from this section.

9. (a) (i) What is meant by the term thermal expansion?

      (ii) Mention two applications of thermal expansion of solids.

(b)    (i) List three areas where bimetallic strips are used.

  (ii) Why a bimetal strip made of brass and invar is curved outside with brass?

(c)    Describe how simple fire alarm system operates.

10. (a) (i) Distinguish between primary and secondary cells, giving one example of each.

(ii) Identify two defects of a simple cell.

(b) (i) Explain why lead – acid accumulators are used in car batteries rather than dry cells?

(ii) A cell of unknown e.m.f, E and internal resistance 2? is connected to a 5? resistance. If the terminal p.d, V is 1.0V. Calculate the e.m.f, E of a cell.

(c) (i) List two devices that are important when checking electrical faults in domestic appliances.

(ii) Briefly explain why a very high voltage is necessary when transmitting electrical energy from power station?

11. (a) (i) What is meant by impulse of a force?

(ii) Briefly explain why seat-belts are designed to stretch in a collision.

(b) i) Define momentum.

1. The cork of a bottle of mass 4 g is ejected with a velocity of 10 m/s in 0.1 second. Find the force exerted on the bottle.

(c)A car of mass 2000 kg is travelling along a straight road at a constant velocity of 10 m/s developing 3.0 kilowatts. If the engine of the car is switched off:

1. Calculate the energy lost by the car in coming to rest
2. Briefly explain the energy changes in the process stated in (c) above.

THE PRESIDENT’S OFFICE MINISTRY OF EDUCATION, LOCAL ADMINISTRATION AND LOCAL GOVERNMENT

PHYSICS- TERMINAL EXAMINATION-MAY

FORM THREE

Time 3:00 Hours                                                                      MAY 2020 

Instructions 

• This paper consists of two sections A B and C. 
• Answer all questions in Section A and B and two question from section C
• Show clearly all working for each question
• Mathematical tables, geometrical instruments and graph paper may be used where necessary 

SECTION A. 15 MARKS

1. (i) A point where the incident parallel rays of light converge or appear to diverge after passing through a lens is called?

1. Center of curvature
2. Focus
3. Optical center
4. Aperture.

(ii) The diameter of a lens is called?

1. Focal length
2. Principal axis
3. Aperture
4. Radius

(iii) Point at which all rays converge in termed as

1. Converging point
2. Focal point
3. Focal center
4. Converging center

(iv) Distance of virtual image and object is equal from mirror. This statement is

1. Right
2. Wrong
3. May be right or wrong
4. Neither right nor wrong

(v) Voltage is a form of:-

1. Kinetic energy
2. Potential energy
3. Both potential and kinetic energy
4. None of the above.

(vi) Ohm’s Law states which relationship between electrical quantities

1. Volts = current  resistance
2. Volts = current amps
3. Volts = coulomb  charge
4. Volts = resistance  charge

(vii) Process of heat transfer that involves continual emission of infrared waves from surface of bodies and transmission of these waves without aid of medium is known as

1. Conduction
2. Convection
3. Radiation
4. None of the above

(viii)Vacuum in a vacuum flask prevents heat transfer through process of

1. Conduction only
2. Convection only
3. Conduction and Convection
4. Radiation only

(ix) The act process or state of change in place or position of a body with respect to time and relative to observes is to be 

1. Rest 
2. Stationery
3. Motion
4. All of above

(x) Which of the following is a type of motion?

1. Circular
2. Rectilinear
3. Periodic
4. All of above

2. Match the following items

           SECTION B. 60 MARKS

3. (a) A Jet air plane travelling at speeding of 500km/h ejects its products of combustions at speed of 1500km/h relative to jet plane. Find speed of the later with respect to an observer on the ground.

(b) A car moving along a straight line with a speed of 126km/h is brought to a stop within a distance of 200m. What is the retardation of the car? And how long does it take for the car to stop?

4. (a) (i) What is meant by specific latent heat of vaporization. 

 (ii) Name two factors which affect the boiling point and freezing point of water.

(b) Explain in terms of kinetic theory of matter;

 (i) What changes is taking place while the liquid is boiling? 

(ii) Why it takes longer time to boil a tea on top of high mountains than at the sea level? 

(c) (i) Define heat capacity

 (ii) Calculate the final temperature of water formed if 8.4 KJ of heat is supplied to 0.02 kg of ice at 0 °C. 

5. (a) What is meant by refraction of light?

    (b) Mention the three points to be considered when drawing a ray diagram to form the    image in lens.

    (c) Mention four effects of refraction of light.

6. (a) What is sea wave energy?

    (b) Explain three ways of harvesting sea wave energy

    (c) Describe challenges of sea wave energy.

7. (a) State what you understand by

1. Magnetic field
2. Magnetic line of force.

(b) Sketch lines of force between (2) bars of magnet placed horizontally on table with;

1. Their N – poles facing each other
2. Their N – poles facing South pole.

    (c) Explain why;

1. Strength of magnet cannot be increased beyond certain limit.
2. Increase in temperature destroys a magnet.

 8. (a) Explain the image formed by curved mirror in terms of:-

1. Position
2. Nature
3. Size

   (b) An object 20cm high is placed 40cm from a concave mirror of focal length 15cm. Determine position, nature and size of image formed by drawing a ray diagram.

 SECTION C

Answer only two questions from this section.

 9. (a) What is a microscope?

    (b)Explain how light microscope works

    (c) Mention three uses of compound microscope.

    (d)What is a projection lantern

    (e) Give five uses of a projectile lantern. 

10. (a) State the energy conversion is a solar cell and give two practical application of it.

 (b) Explain why solar cells are not likely to be used to generate electricity in future?

 (c ) Discuss the problems associated with fuel energy to the environment.

 11. (a) Define the following terms; 

(i) Evaporation (ii)Temperature.

(b) Give four differences between boiling and evaporation. 

(c) An immersion heater rated 2kW is used to heat water of specific heat capacity 2200j/kgK in an insulated container of negligible heat capacity for 30minutes. Calculate the mass of water heated if the temperature of water rises from  20°C to 65°C. 

THE PRESIDENT’S OFFICE

MINISTRY OF EDUCATION AND VOCATIONAL TRAINING

MID TERM EXAMIATIONS

031                                                                 PHYSICS- THREE

Duration: 2:30 Hours

INSTRUCTIONS.

1. This paper consists of sections A, B and C with a total of TEN (10) questions.
2. Answer all questions 
3. All writing must be in blue or black ink except drawing which must be in pencil.
4. Calculators, cellular phones and any unauthorized materials are not allowed in the examination room.
5. Write your Examination Number at the top right corner of every page.
6. Where necessary the following constant may be used; 

1. Acceleration due to gravity, g = 10m/s²
2. Density of water = 1g/cm³ or 1000kg/m³

SECTION A (15 Marks)

Answer all questions in this section.

1. For each of the items (i)­(x), choose the correct answer among the given alternatives and write its letter beside the item number in the answer booklet provided.

(i)        The irregular motion of tiny particles suspended in a fluid is called; 

1. Mobility   
2. B. Kinetic motion    
3. C. Random motion   
4. D. Brownian motion 

(ii)       The colours which are added together to produce white light are called complementary colours, which of the following are complementary colours;

1. Red and Cyan    
2. B. Magenta and Blue    
3.  C. Random and motion 
4. D. Brownian motion 

(iii)      The property of the material to recover its original shape and size on removal of a stretching force is called;

1. Elasticity    
2. B. Plasticity    
3. C. Hooke’s law     
4. D. Cohesively 

(iv)      A vector has both magnitude and direction and the examples are;

1. Work and displacement 
2. displacement and speed 
3. speed and momentum 
4. acceleration and momentum 

(v)       The laws of vector addition are; 

1. The triangle law only. 
2. The triangle law and the polygon law only 
3. The polygon law, triangle law and the parallelogram law. 
4. The parallelogram law. 

(vi)      The forces of 4N and 3N act on a body due East and North respectively. The resultant force is; 

(vii)     The forces F₁ = 5N, F₂ = 13N and F₃ are the equilibrium forces which act on a body as shown in the figure below; 

                                    F3                         F2

                                                            F1 

                The Magnitude of F3 is;

(viii)    The relative velocity of a body is the velocity of a body with respect to another; 

1. body at rest. 
2. moving body or at rest 
3. body of smaller mass
4. body of higher velocity 

(ix)              A floating body experiences an upthrust which is equal in magnitude to the; 

1. Weight of the fluid displaced 
2. Weight of the fluid which the body floats 
3. Density of the fluid displaced 
4. Weight of the body when filled with the displaced fluid 

(x)               A bus carrying a very big load on its carrier can easily overturn because; 

1. It cannot run fast 
2. Its equilibrium is state 
3. Its centre of gravity is low 
4. Its centre of gravity is high 

2. Match the times in List Awith responses in List B by writing the letter of the correct response beside the item number in the answer booklet provided.

SECTION B. 60 MARKS

3.     (a) (i)What effect does an increase in temperature have on the density of most liquids? 

       (ii) Explain the procedure of using methylated spirit, water and a pendulum bob to   find the relative density of spirit.                                                                                                                                                             

        (ii) Briefly explain why does a ship sink deeper in fresh water than in sea water?       

1. When a piece of wood is put in a graduated cylinder containing water, the level of     the water rises from 17.7cm³to 18.5cm³. Calculate the
2. Mass of a piece of wood.
3. Total volume of a piece of wood given that its relative density is 0.60.                       

4. (a) Define the term friction. 

(b) State the advantages and disadvantages of friction. 

(c) State the laws of solid friction. 

(d) A box of mass 50kg resting on a wooden floor force. Calculate the frictional force if the coefficient of dynamic friction 

5. (a) Define pressure and state the SI unit. 

(b) A Hare’s apparatus was used in experiment using methanol water the length’s of the methanol and water columns were found to be 16cm and 12cm respectively. Find the relative density of methanol   if the length column of the ethanol was altered to 22cm. 

6. (a) State and describe two factors on which pressure exerted by the liquid depends. 

(b) Hydraulic press has a large circular piston of diameter 0.7M and circular piston to which the effort is applied is 0.2M. A force of 300N is exerted on a small piston. Find the force required to lift the  heavy load. 

7. (a) Whenever you want to remove a very tight nut from your bicycle you have to choose a longer  spanner, why is it so? 

(b) A rocket expels gas at the rate of 0.5kg/s. If the force produced by the rocket is 100 newtons, what  is the velocity with which the gas is expelled? 

8. A vehicle moves from rest with a uniform acceleration of 1.5m/s² for the first 10s and continues accelerating at 0.5m/s² for a further 20s. It continues at constant speed for 90s and finally takes 30s to decelerate uniformly to rest. 

1. Draw a graph of speed against time for the journey. 
2. From your graph, reduce the total distance travelled. 
3. What is the average speed of the train for the whole journey? 

SECTION C. 25 MARKS

Answer all questions in this section

9. (a) Mention two conditions for an object to remain in equilibrium when subjected to a number of parallel forces

(b) A uniform bar 100cm long weighing 90g is suspended horizontally by two spring balances each holding the ends x and y. an 80g mass is hang 40cm from the end x. Calculate the reading of each spring balance in grams.

10. (a) Mention two factors affecting pressure in liquids

(b) Calculate pressure exerted by water at the bottom of a pond 76cm deep

(c) Mention any three applications of atmospheric pressure 

11. Define the following terms;