PRESIDENT OFFICE REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

SECONDARY EXAMINATION SERIES 

COMPETENCE BASED ASSESSMENT

031/1 PHYSICS FORM THREE 

MID-TERM EXAMS MARCH – 2023 

Time: 3 Hours 

Instructions

1. This paper consists of section 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 (16) marks, section B sixty (54) marks and section C carries twenty five (30) marks
4. Cellular phones and any unauthorized 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)
7. Where necessary the following constants may be used:

1. Acceleration due to gravity, g=10m/s²
2. Density of water = 1.0g/cm³
3. Pie, π = 3.14
4. Speed of light waves = 3.0 x 10⁸m/s

SECTION A (16 marks)

1. For each items in (i) – (x) choose the correct answer from among the given alternative and write its letter in box provided

1. In a process of charging by induction in static electricity

1. A conductor is rubbed with an insulator
2. A charge in procedure by friction
3. Negative and positive charges are separated
4. A positive charge includes a positive charge
5. Elections are sprayed into an object.

2. 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 distance under its distance-time graph
4. The slope of the distance-time graph
5. The slope of peak of its distance time-graph

3. Which of these energy is non-renewable?

1. Ware energy
2. Bio fuels
3. Radiant energy
4. Fossil fuel
5. Geothermal energy

4. _____ is the area around a magnet current carrying conductor where magnetic strength can be detected by compass

1. Magnetic domain
2. Magnetic field
3. Magnetic poles
4. Induced filch
5. Neutral point

5. Which of the following apparatus is used to measure volume of irregular solid?

1. Pipette
2. Beaker
3. Measuring tape
4. Measuring cylinder
5. burette

6. A car moving with a velocity of 40km/h can be stopped by applying braces in2m. If the same car is moving with speed of 80km/h, what is the minimum stopping distance?

1. 16m
2. 12m
3. 8m
4. 4m
5. 2m

7. What are two factors that determine Buoyancy?

1. Volume of fluid displaced and mass of the object
2. Weight and mass of object
3. Density of fluid and weight of object
4. Volume of fluid displaced and density of fluid
5. Mass of object and density of object.

8. Which physical phenomenon is observed when tea bag is dipped into a cup of hot water?

1. Steaming
2. Diffusion
3. Osmosis
4. Evaporation
5. Boiling

9. Which process is involved in producing reverberation?

1. Refraction
2. Multiple reflection
3. Interference
4. Diffraction
5. Reflection

10. Which of the following is a scalar quantity

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

2. Match each item in List A with a correct response in LIST B by writing a letter of correct response below the number of corresponding item in LIST A in table provided.

SECTION B (54 Marks)

Answer all questions in this section

3. (a)Vectors are direction. What do you think are two conditions to be satisfied for two vectors to be equal?

(b) State and explain practical meaning of Triangle law of vector addition

(c) Two vectors, one of 8N and another 16N are acting on a body. Give that the two forces are acting perpendicularly to each other. Find the magnitude of the third force which would just counter balance the two forces.

4. (a)how are the principle focus of a convex mirror explained as far light in concerned

(b)A concave mirror is used to form an image of an object pin where the object must be placed to obtain,

1. Upright enlarged Image
2. Image same size an object

(c)A diagram below shows the path of a ray of light through one corner of a cube ice. Finds,

1. Angle of incidence as the AB
2. The angle of refraction of this face

5. (a)A uniform half meter rule in balanced at 15cm marks when a load of 0.4N is hanging at the zero marks. Draw a sketched diagram indicating the arrow of weight of the rule acting through the centre of gravity hence determine the weight of the half meter rule.

(b)Screw Jack has a screw pitch of 5mm and effort arm of 16cm

1. State two forms of energy in which the energy supplied to screw jack is finally converted to
2. Determine the percentage efficiency of Screw jack if it need an effort of 30N to left a load of 750N

6. (a)State one use of convex mirror and indicate why it is preferred to a plane mirror

(b)An object in set 20cm in front of a lens and the real, inverted, magnifies and at greater distance image was formed. State the type of lens used and determine the value of focal length.

7. (a) state Newton’s laws of motion

b) (i). Give reason why a person doing high jump bend a little his legs on landing 

(ii). Why it’s necessary to use seat belt in a car?

c) A tennis ball whose mass is 150 g is moving at a speed of 20 m/s. it is then brought to rest by one player in 0.05 s. find average force applied

8. (a) (i) When the pulling force is applied to the handle of the door, the hinge acts as the axis of rotation, and the door turns about. What do you understand by the term turning effect?

(ii) When forces are in equilibrium, it means that there is no net force to cause any movement. Describe conditions for parallel forces to be in equilibrium.

(b) A heavy uniform metal beam AB weighting 500kg is supported at its ends. The beam carries a weight of 3000kg at a distance of 1.5m from end A. If the beam is 4m long, determine the thrusts on the supports A and B.

SECTION C (30 Marks)

Answer any two questions from this section

9. (a) A form two student is in the physics laboratory. He is provided with density bottle, sand, digital balance and water. He is required to determine the density of sand using the instruments provided above, show how will he determine the density of the sand?

(b) In an experiment to determine the density of sand, Sophia obtained and recorded the following results.

Mass of the density bottle, M1 = 200g

Mass of density bottle and sand, M2 = 490g

Mass of density bottle, sand and water, M3 = 550g

Mass of density bottle and water, M4 = 300g

(i) What was the density of sand?

(ii) Determine the relative density of sand.

10. (a) You are provided with two types of mirrors, concave mirror and convex mirror. What type of the mirror among the two will you prefer or driving a car to see the traffic at your back? Explain your choice.

(b) A far-sighted woman has a near point of 1.5m. Calculate the focal length of the lens for her ` eyeglasses so that she can read a book held at 25cm. Also find power of the lens.  

11. (a) A pressure cooker will cook beans faster than an open saucepan. Give explanation on these observations.

(b) An insulated cup holds 0.3kg of water at 0^oC. 0.2kg of boiling water at standard pressure is poured into the cup. What will be the final temperature?

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 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;