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

COMPETENCY BASED SECONDARY EXAMINATION SERIES

                                                     PHYSICS   FORM FOUR

TIME: 3 HOURS                                                                      NOVEMBER 2022

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 alternative and write its letter beside the item number in the booklet provided. (10 marks)

(i)      In the reading 2.24mm, being read by a micrometer screw gauge, which figure represent the thimble scale?

A.   2.20mm 

B. 2.00mm

 C. 0.04mm

 D. 0.24mm

E. 0.42mm

(ii)   A constantan wire of diameter 0.4mm has a resistance of IOQ. What is its length if the resistivity of the wire is 5.0 x 10-7 Qm?

A.   0.39m  

B. 2.52m

C. 3.62m 

D. 2.51mm 

E. 0.93m

(iii)   In the figure below, plates P and Q have the vertical large positive and negative Charge respectively. When a small conducting sphere with a positive charge is suspended between P and Q, it swings to Q and then keeps oscillating from Q to P and back. This is because:-

A.   P has a greater charge than Q B. S is attracted by and repelled by Q

C.   Q has a greater charge than P

D.  S is always repelled from P and attracted by Q

E.   S receives a smaller charge from P and Q each time it touches the plates

(iv)   The energy charges that takes place after the push switch is depressed in an electric bell are in order of:-

 (v)   In a single rope 4 -pulleys system, the mechanical advantage is less than 4 because

A.   The effort may vary

B.   Friction acts on the pulleys

C.   The load is raised

D.   The upper pulleys don't move

E.    The weight of the lower pulleys can be neglected

 (vi) When a person perspires on a hot day

A.   Evaporation occurs and helps to cool the body

B.    Heat is conducted away from the body

C.    Latent heat keeps the body warm

D.   The body is insulated from the warm air

E.    Convection cools the body

(vii)      A typist uses new carbon -paper under her top typing paper for making a copy of the letter. When she holds the carbon - paper close the plane mirror, she can read the letter. This is because the mirror

A.   Forms an image of the same size

B.    Produces a lateral inverted imago

C.    Forms and image behind the mirror

D.   Produces an inverted image

E.    Forms a virtual image

(viii)   The figure below shows the motion of radiation emitted from a certain source

The order of increasing penetrating power of radiations is

(ix)        The energy from the hot rocks within the earth is called

 A. Tidal energy

B.   Water energy

C.   Geothermal energy

D.   Biomass energy E. Wave energy

(x)           When a car moves round a circular path at a constant speed, which of its motion properties is constant throughout?

A.   Displacement

B.    Velocity

C.    Acceleration

D.   Momentum

E.    Kinetic energy

2.  Match the items in list A with responses in list B by writing the letter of the correct response below the item number in the answer sheet provided. (05 marks)

SECTION B: (60 MARKS)

Answer all questions from this section

3.  (a) Describe the energy changes which occur when the device which illustrates the principle of conservation of energy operates (05 marks)

(b)An Astronant weighs 900N on the earth and 150N on the moon. Explain why this is so and determine the moon's gravitational strength (05 marks)

4.  (a) (i) Why does dust fly off when a carpet is hit with a stick? (02 marks)

(ii) Why does a cyclist often zig- zag motion when going up a hill (03 marks)

(b)The figure below shows a box whose weight along the inclined plane is 300N

(i) Calculate the work done in sliding the box up the inclined plane from P to Q (02¹/2 marks)

(ii) Find the power used if it took 5 minutes to move the box from P to Q (02¹/2 marks)

5.  (a) A passenger ferry with vertical sides has a water line areas of 1500m ² when fully loaded with passengers it sinks by 0.6cmr if the average mass of a passenger is 60kg, calculate the number of passengers on the board (06 marks)

(b)Briefly explain the two applications of total internal reflection of light in daily life (04 mårks)

6.  (a) Explain how cathode rays are produced in a cathode ray tube (04 marks)

(b)A weight of 50N suspended from a beam by a string. What is the tension in the string so as the weight to be remained in equilibrium, if the string makes an angle of 40⁰ to the horizontal (06 marks)

 7. (a) In Tanzania we have uranium materials, explain what do you think will the country benefit from using uranium in the nuclear power plant? (02 marks)

(b) (i) Observe and explain at least four (4) important signs that are seen before an  earthquake occurs (06 marks)

(ii) Explain the force that keeps the earth in its position (02 marks)

8.   (a) (i) A galvanometer has a resistance of IOOQ and gives a full — scale deflection of IA. What shunt must be used to make the meter suitable to measure current up to 5A? (03 marks)

(ii) What resistance must be connected in series with the meter of the galvanometer in (a) (i) above so that it can be used as voltmeter to read up to IV? (03 marks)

(b)The figures below shows water waves mixing within two region in a ripple tank. The Oyo regions have different depth

 (i)      In which region are the waves moving faster? (03 marks)

(ii)  Which part of the ripple tank is deeper? (01 mark)

SECTION C: (25 MARKS)

9.      (a) (i) How does a stretched string on being set into vibration, produce an audible sound? (02 marks)

(ii) Will this sound be audible it the string is set into vibration of the surface of the moon? (Give reasons for your answer) (1 ¹/2 marks)

(b)The rear view mirror of a motor bike starts vibrating violently at some particular speed of the motor bike

(i)     Why does this happen? (02 marks)

(ii)  What is the name of the phenomenon taking place? (0lmark)

(iii) What could be done to stop the violent vibrations? ( 1 ¹/2 marks)

(c)Find the speed of sound in air at 25⁰C (04 marks)

10.  (a) 0.2kg of alcohol is contained in a vessel of heat capacity 80J/k, when heated for 9 minutes by a 50W immersion heater the temperature rises from 15⁰C to 65⁰C. Find the specific heat capacity of alcohol (07 ¹/2 marks)

(b)An electrical appliance is rated 1500W, 20V this appliance is connected to 250V mains.

Calculate the cost of electrical energy consumed in 60 hours at 2.50 Tsh per kWh. (05 marks)

11.   (a) The figure below shows a circuit diagram for single stage amplifier. Identify the type of amplifier represented by that diagram. Give reasons for your answer (01 ¹/2 marks)

(b)     Explain the mode of action of a p -n junction (05 marks)

(c)     (i) Explain how ozone layer depletion occurs (02 marks)

(ii) Briefly explain the harmful effects results from the depletion of ozone layer. (04 marks)

THE PRESIDENT’S OFFICE

MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

COMPETENCE BASED SECONDARY EXAMINATION SERIES

PHYSICS TERMINAL EXAMINATION

FORM FOUR-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. High voltage is used for transmitting electricity on the National Grid. This is because high voltage

1. is needed everywhere
2.  means high current would be used
3.  needs transformers for conversion
4.  would minimize electrical energy losses by using low current.
5. would facilitate power distribution to customers.

2. Polarization is

1. the cell defect caused by impurities in zinc plate
2.  the formation of hydrogen gas around the positive plate of an electric cell
3. the formation of tiny cells around zinc plate
4. the cell defect that can easily be corrected by amalgamation
5. the process of giving polarity

3.                     A transistor is a device which

1. amplifies alternating current or voltage
2. amplifies direct current or voltage
3. rectifies direct current or voltage
4. amplifies and rectifies alternating current or voltage
5. Rectifies alternating current or voltage.

4.                      What causes water tides in the sea?

1. Rotation of the earth about the sun
2. Rotation of the moon about the earth
3. Rotation of the earth about its axis
4. Gravitational force due to the earth on the sea
5. Gravitational force due to the moon on the sea

5. Which is an incorrect statement about the solar planets?

1. They are always moving in space
2. They are all non ­luminous
3. They all revolve round the sun as their centre
4. They all have at least one moon
5. The brightest planet as observed from the earth is venus.

6.                      Which of the following are inner planets?

1. Mercury and Venus
2. Jupiter and Mars
3. Saturn and Venus
4. Neptune and Uranus
5. Pluto and Mars.

7.                   One use of gamma ­rays (ᵧrays) is to

1. treat neurotics
2. treat black spots
3. heal fractures
4. kill cancer cells
5. join broken hands.

8.                The conduction in a semi conductor material is due to

1. doping
2. extrinsic conduction
3. intrinsic conduction
4. motion of charges
5. movement of holes and electrons.

9.                      Compared to cool air, warm air can hold

1. more water vapour
2. less water vapour
3. the same amount of water vapour
4. no water vapour
5. more or less the same amount of water vapour.

10. Which of the following is correct about a capacitor?

1. Does not need an insulator between its plates
2. Has very high capacitance when air is between its plates
3. Must have metal plates to store a charge
4. Has capacitance defined by C = V/Q
5.  Has no voltage across it when working in a radio receiver.

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) Define the terms

(i) Half life (ii) atomic number

(b) Name the three fundamental particles of which atoms of an element are composed. How are these particles distributed in the atom of an element whose atomic number is 3 and mass

number7?

(c) A radioactive nucleus is denoted by the symbol 88X226

Write down the compositions of the nucleus at the end of the following stages of disintegration

(i) Emission of an alpha (∝) particle

(ii) Further emission of beta (β) particle

(iii) Further emission of a gamma radiation

4. (a) (i) Distinguish between mechanical and electromagnetic waves

(ii) Explain why a duck remains floating at the same place as a wave passes by the water in a lake

(b) (i) What are ultrasonic vibrations?

(ii) An FM radio station broadcasts electromagnetic waves at frequency of 125 M Hz. The radio waves have a wavelength of 2.4 metres. Calculate the speed of the radio waves

(c) Gamma ray busters are objects in the universe that emit pulses of gamma rays with high energies. The frequency of the most enegetic bursts has been measured at round 3.0 x 1021 Hz.

(i)What is the wavelength of these gamma rays?

(ii)What could be their period?

5. (a) A body projected vertically with a velocity of 40m/s from the ground, comes to rest momentarily at the top most position and returns to the ground. Calculate; (i) The maximum height reached by the body  (ii) The total time of flight

(b) In figure below, a force of 100N acts on the smaller piston of area 2cm². Calculate the upward force acting on the large piston of area 900 cm².

(c) A body of mass 400g falls freely from a tower and reaches the ground after 4s. Calculate the kinetic energy of the mass as it hits the ground. (Take g= 10m/s²)

6. (a) A machine is used to lift a load of 400N with an effort of 80N.

Calculate

1. The mechanical advantage of the machine,
2. The efficiency of the machine, if the velocity ratio of the machine is 8

(b)A spiral spring produces an extension of 4cm when a force of 2N is applied to it. Calculate the spring constant for a system when two such identical springs are arranged in (a) series (b) parallel

(c)A metal block of density 7 800kg/m³ weighs 117N in air and 105N in a liquid when wholly immersed wholly immersed. Calculate the density of the liquid.

7. (a) Name two objects in space which are the earth’s nearest neighbours

(b) What are the real names of objects in the sky which are commonly known by the following names?

(i) An evening star

(ii) A morning star

(iii) A shooting star

(c) The earth appears to be stationary, but it is always in motion. Calculate the unnoticed speed of a man along

the equator, in km/h,due to

(i). Rotational motion of the earth about its axis

(ii). Revolution of the earth around the sun

Take 1 year = 365 days

8.(a) Define the following terms.

(i) Capacitor

(ii) Semi-conductor

(iii) Transistor

(b) What are the differences between a conductor, a semiconductor and an insulator in terms of their conductivity?

(c) An output of transformer is connected in series with semiconductor diode

(i) Draw the sketch of the expected variation of electromotive force against time.

(ii) Give reasons whether this device is suitable or not for use in a radio.

9. (a) Sketch the magnetic field patterns due to a current passing through

(i) a long straight wire (ii) a circular coil (iiii) a long solenoid

Indicate clearly the direction of current and magnetic field.

(b) Explain briefly how the domain theory of magnetism is used to differentiate a magnetic material from a magnet

(c) (i) Describe how sounds are transmitted by telephones,explaining the actions of both transmitter and receiver.

(ii) What additional equipment is needed to ensure good communication over long distance?

SECTION C (10 Marks)

Answer one (1) question from this section.

10. (a) Using Newton’s second law of motion, state two quantities which vary with net force

applied on a body. (02)

(b) Write an equation obtained by combining the force and the two quantities you have

mentioned. (02)

(c) Evaluate the proportionality constant if your equation is used to define the unit of force,

the Newton, while taking a unit of each variable in your equation. (01)

(d) A certain force gives a mass m 1 an acceleration of 12.0 m/s 2 . What acceleration will the

same force give the two masses when they are joined together? (04)

11. (a) (i)Use the kinetic theory to explain why solids expand when heated.

 (ii)Mention two experiments which can be done in the laboratory to verify thermal expansion of solids. 

(b) Explain how each of the following works:

(i) a bimetallic thermostat.

(ii)a bimetallic thermometer.

(c) (i) What is an induction coil?

(ii) Describe the structure of an induction coil and briefly explain its mode of action.

THE PRESIDENT'S OFFICE

MINISTRY OF REGIONAL GOVERNMENT AND LOCAL GOVERNMENT

MID TERM-1 EXAMINATION

PHYSICS FORM-4

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) What physical phenomenon is observed when a tea bag is dipped into a cup containing hot water?

1.  Surface tension
2.  Capillary then diffusion
3.  Diffusion
4.  Osmosis then diffusion 
5.  Osmosis only. 

(ii) When a gas is compressed at constant temperature, the gas molecules

1.  move faster than air outside and the pressure is increased
2.  move with uniform speed and the pressure is unchanged
3.  gain more kinetic energy and the pressure is decreased
4.  increase slightly in size and its pressure remains constant
5. make more impacts per second on the walls of the container.

 (iii) 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. 

(iv) 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.

(v) The correct statements about sound waves is that they

1. are transverse waves
2. can travel in vacuum
3. can be polarized
4. cannot be polarized
5. do not require medium.

 (vi) In order to produce electrons in a discharge tube the

1. anode should be at a higher potential than the cathode
2. potential difference at the anode should be low
3. cathode should be heated indirectly at low voltage supply
4. electrodes should be at the same potential
5. electrons must be accelerated at higher potential.

(vi)The note from a plucked guitar will have a low pitch if the string is

1. thick and long
2. thick and slack
3. thin and slack
4. thin and short 
5. thick and short.

 (vii)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.

(ix) In a race competition, one should kneel down when starting the race so that:

1. no one can fall down by reaction produced by the earth to them. 
2.  each one can receive an acceleration which the earth provides.
3.  one of the rules in sports is not violated by anyone.
4. equal and opposite forces can act on a body to produce a resultant force.
5. each one could exert a force on the surface of the ground.

 (x) The destruction of ozone layer in the atmosphere has led the world to disasters caused by:

1. absorption of the background radiation. 
2. poor handling of the radioactive materials.
3.  the increase of the ultra-violet radiations on the earth. 
4.  poor utilization of radioactive materials. 
5.  poor disposal methods of radioactive remains.

2. Match the functions of instruments in List A with their corresponding instruments in List B by writing the letter of the correct response beside the corresponding item number in the answer booklet provided. (5 marks)

SECTION B (60 Marks)

Answer all questions in this section.

3. (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?

4. (a) (i) Define the term semiconductors.

(ii) How do intrinsic semiconductors differ from extrinsic semiconductors?

b) (i) List four properties of cathode rays.

(ii) Describe how x-ray tube is used to produce x-rays.

(c) (i) Mention three uses of induction coil.

(ii) Briefly explain the working principle of a bicycle dynamo.

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) (i) Define the term wavelength.

(ii) How does the size of the gap in the barrier affect the diffraction of waves?

(b)(i) State two ways in which visible light differ from radio waves.

(ii) List two applications of gamma rays.

7. (a) (i) State the law of inertia

(ii) Use the law in (a) (i) to define force.

(b) A ticker – tape is moved through a ticker – timer for 5.0 seconds. If the timer is operating at 25 Hz:

1. How many dots would have been printed on the tape?
2. What kind of motion does the tape represent? Give a reason.

(c) A shell of mass 30kg is fired at a velocity of 600ms^-1 from a gun of mass 7000kg.

1. What is the recoil velocity of the gun?
2. Briefly explain the significance of the answer obtained in (c) (i) above.

8. (a) What is meant by the following terms?

(i) Resonance

(ii) Overtones.

(b) Briefly give reasons for the following:

(i) the fundamental frequency may alter during the day.

(ii) notes of the same pitch played on a violin and a flute sound different.

(c) The frequency obtained from a plucked string is 400 Hz when the tension is 2 N. Calculate:

(i) the frequency when the tension is increased to 8 N.

(ii) the tension needed to produce a note of frequency of 600 Hz.

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

(ii) Mention three points to be considered when drawing a ray diagram to show the formation of images on a concave mirror.

(b)(i)Briefly explain why part of the road ahead of a person apparently looks as if it has a pool of water on a sunny day?

(ii) A pin is at the bottom of a vessel 16 cm deep. When the vessel is filled with water the pin appears to rise when viewed form above. Find the height to which the pin appears to rise. 

(c) Paraffin has a greater refractive index than water. What can you say about the 

 (i) relative velocity of light in paraffin and in water?

(ii) path of a ray of light when passing from water into a layer of paraffin?

10. (a) Mention three differences between boiling and evaporation.

(b) Briefly explain reasons for the following:

1. When a cold bottle is brought into a warm room, it becomes misted over
2. Frost is more likely to occur on a clear night than on a cloudy night.

(b)(i) Define coefficient of linear expansion and give its SI unit.

(ii) A metal pipe which is 1 m long at 40°C increases in length by 0.3% when carrying a steam at 100°C. Find the coefficient of expansion of the metal.

11.(a) Define the following terms:

(i)Newton.

(ii)Inertia.

(iii)Linear momentum.

(b) Two stones are thrown vertically upwards from the same point with the same velocity of 20 m/s but at an interval of 2 seconds. When they meet, the second stone is rising at 10 m/s. Calculate:

(i) the time taken by the second stone in air before they meet (ii) the velocity of the second stone when they meet.

(c) A stationary bomb of mass 5 kg explodes into one part A of mass 2 kg flying off with a velocity of 60 m/s and another part B of mass 3 kg flying off with a certain velocity in the opposite direction. Calculate the

(i)velocity of part B

(ii)total kinetic energy produced by the explosion.

THE PRESIDENT'S OFFICE

MINISTRY OF REGIONAL GOVERNMENT AND LOCAL GOVERNMENT

PRE-NATIONAL  EXAMINATION SERIES-1

PHYSICS  FORM-4

2020

TIME: 3:00 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/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.

(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 statement explains the basis of heliocentric theory?

1. The earth was known to revolve around the sun
2. The earth was stationary
3. The sun was known to revolve around the earth
4. The sun was stationary
5. The earth was known to revolve around its axis.

(iii) Which among the following is a reason for the sky to appear blue while being observed from the earth?

1. Regular reflection of sunlight
2. Irregular refraction of sunlight
3. Diffuse refraction of sunlight
4. Selective scattering of sunlight
5. Regular diffraction of sunlight.

(iv) 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.

(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 loudness of a note produced by a vibrating object depends on?

1. The number of vibrations per second
2. The overtones present
3. The quality of sound
4. The wavelength between two nodes
5. The amplitude of vibration.

(vii) In a black and white television, the image is formed on the screen by:

1. varying the intensity or brightness of the electron beam
2.  adjusting the number of stations using a remote control
3.  limiting the flow of electrons between the cathode and anode
4.  increasing the grid’s voltage to its maximum value
5.  adjusting the antenna to capture waves of short wavelength. 

 (viii) 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. 

(ix) Figure 1 shows a pattern of waves in a ripple tank traveling from part X to part Y across a plane section Z.

Figure 1

What observation can be made from Figure 1?

1.  the total reflection occurs at Z
2.  the wavelength in part X is greater than that in part Y
3.  the wave speed v1 in part X is less than v2 in part Y
4.  diffraction occurs across Z
5.  The wave changes in frequency as it crosses Z. 

 (x) 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 

2. Match the items in List A with 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) 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. 

 4(a) (a) Why the inner core of the earth is solid while the outer core is liquid? Briefly explain.

(b) The frequency obtained from a plucked string when the tension is 2 N is 400 Hz. Calculate the frequency when the tension is increased by 6 N.

5. (a) A sample of carbon isotope ¹⁴₆C has a half-life of 5700 years. What fraction of ¹⁴₆C will remain after 11400 years?

 (b) Describe the construction and mode of action of the PN junction semiconductor.

6. (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.

7. (a) (i) Define the term astronomy.

  (ii)Enumerate three importance of astronomy to mankind.

(b)    (i) Specify the difference that exists between galaxy and a planet. (ii) Outline three defining characters of a planet. 

8. (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?

SECTION C (25 Marks) 

Answer two ( 2) question from this section. 

9. (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?

10. (a) What is meant by the following terms?

(i) Asteroids.

(ii) Astronomy.

(b) Distinguish between:

(i) Constellations and a galaxy.

(ii) Meteor and meteorites.

(c) (i) Mention two types of tides.

(ii) With the aid of diagram, describe how ocean tides are formed.

11 (a) (i) Define the term semiconductors.

(ii) How do intrinsic semiconductors differ from extrinsic semiconductors?

(b) (i) List four properties of cathode rays.

(ii) Describe how x-ray tube is used to produce x-rays.

(c) (i) Mention three uses of induction coil.

(ii) Briefly explain the working principle of a bicycle dynamo.

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

PHYSICS- POST-MOCK- EXAMINATION-JUNE

FORM FOUR

Time 3:00 Hours JUNE 2020

1. This paper consists of sections A, B and C.
2. Answer all questions in sections A and B and one (1) question from section C.
3. Calculators and cellular phones are not allowed in the examination room.
4. Write your Examination Number on every page of your answer booklet(s).
5. Where necessary the following constants may be used:

• Acceleration due to gravity, g = 10 N/kg or 10 m/s²
• Density of air = 1.2 kg/m³
• Density of mercury = 13200 kg/m³
• Density of water = 1000 kg/m³
• Linear expansivity of steel = 11 x 10^-6 K^-1
• Pi, π = 3.14

SECTION A (15 Marks)

Answer all questions in this section.

(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) A layer of colorless water floating on a blue copper (II) sulphate solution becomes blue after sometime. Which physical process supports the observation made?

1. Diffusion
2. Cohesive
3. Surface tension
4. Adhesive
5. Osmosis

(iii) Which phenomena is a result of the earth being exactly along the same line between the centre of the sun and the moon?

1. Lunar eclipse
2. Penumbra
3. Solar eclipse
4. Umbra
5. Reflection

(iv) A body moved upward a distance of 20 m. Calculate the time taken to reach the maximum height.

1. 2 s
2. 5 s
3. 10 s
4. 15 s
5. 11 s

(v) Which factors influence friction between tyres of a car moving with constant speed and surface of the road?

1. Weight and speed
2. Speed and nature of the surface
3. Nature of the surface and weight
4. Surface area of the tires and speed
5. Acceleration and nature of the surface

(vi) 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 conducts thermal energy to the wheel.
5. It is because the sun conducts thermal energy to the wheel.

(vii)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.

(viii) 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

(ix)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.

(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 2.20?

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

(ix)Where are asteroids found in the solar system?

1. Between Mercury and Venus
2. Between Earth and Mars
3. Between Mars and Jupiter
4. Between Saturn and Uranus
5. Between Neptune and Pluto

(x) What fraction of the atoms would have been disintegrated in 72 hours when the half-life of an element is 24 hours?

1. 1/8
2. 1/2
3. 3/4
4. 7/8
5. 1/4

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) Mention four applications of thermal expansion of solids.

(b) Briefly explain why holes are left below the chimneys of kerosene lamp or kitchen.

(c) A steel tyre of diameter 150 cm at 10°C is to be fitted on to a train wheel of diameter 151 cm. What temperature must the tyre be heated to just fit the wheel?

4.(a) (i) Define the term wavelength.

(ii) How does the size of the gap in the barrier affect the diffraction of waves?

(b)(i) State two ways in which visible light differ from radio waves.

(ii) List two applications of gamma rays.

5. (a) (i) What is meant by mutual induction.

(ii) Illustrate how the right hand grip rule is used to determine electric current and magnetic field directions.

(b) (i) Draw the diagram of direct current (d.c) generator showing its important parts.

(ii) Briefly explain how simple a.c dynamo can be converted to simple d.c dynamo.

6. (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?

7. (a) (i) State the law of inertia

(ii) Use the law in (a) (i) to define force.

(b) A ticker – tape is moved through a ticker – timer for 5.0 seconds. If the timer is operating at 25 Hz:

1. How many dots would have been printed on the tape?
2. What kind of motion does the tape represent? Give a reason.

(c) A shell of mass 30kg is fired at a velocity of 600ms^-1 from a gun of mass 7000kg.

1. What is the recoil velocity of the gun?
2. Briefly explain the significance of the answer obtained in (c) (i) above.

8. (a) What is meant by the terms

1. Bimetallic strip
2. Linear expansivity of the solid

(b) Briefly explain on the following observations:

1. In cold weather the metal blade of a knife feels cooler than the wooden handle.
2. A cool breeze blows from the sea on a hot summer day.

(c) (i) Define latent heat of fusion of a substance

(ii) A copper block of mass 0.68 kg is suspended in a freezing mixture at - 50 for some time and then transferred to a large volume of water at 0 . Calculate the mass of ice formed.

9. (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.

SECTION C.
Answer one question.

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) Define the term semiconductors.

(ii) How do intrinsic semiconductors differ from extrinsic semiconductors?

b) (i) List four properties of cathode rays.

(ii) Describe how x-ray tube is used to produce x-rays.

(c) (i) Mention three uses of induction coil.

(ii) Briefly explain the working principle of a bicycle dynamo.

031

THE PRESIDENT’S OFFICE
REGIONAL ADMINISTRATION AND LOCAL GOVERMENT
 FORM FOUR MID TERM EXAMS

PHYSICS

TIME: 3 HOURS                                                                                                                                           2020

INSTRUCTIONS

1. This paper consists of sections A, B, and C.
2. Answer all questions in sections A and B and one(1)question from section C.
3. Calculators and cellular phones are not allowed in the examination room.
4. Write your Examination Number on every page of your answer booklet(s).
5. Where necessary the following constants may be used:

Acceleration due to gravity, g = 10m/s²

Density of water = 1.0 g/cm³

Linear expansivity of iron = 1.24×10^­5K^-1 Specific latent heat of fusion of ice = 336J/g Velocity of sound in air = 340m/s

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 beside the item number in the answer booklet provided.

(i) A spiral spring of natural length 1.50m is extended to 1.505m by a force of 0.80N

What will be its extension when the applied force is 3.20N?

A. 0.005m                                         

B. 6.020m                                         

C. 0.020m

D. 4.520m                                                      

E. 1.57.

(ii)            Which of the following electromagnetic waves is used to detect flaws and defects in

steel plates?

A. infrared waves                                           

B. ultraviolet waves                         

C. x­rays

D. gamma rays                                                                                 

E. micro waves.

(iii)           A part of human eye that corresponds to the film in a camera is called

A. cornea                                          

B. iris                                                 

C. lens

D. pupil                                                            

E. retina.

(iv)           The sun generates its energy by a process called

A. thermonuclear fission                                                                    

B. thermonuclear fusion

C. geothermal energy                                                                                                   

D. geothermal fusion

E. geothermal fission.

(v)            What will be the size of the image formed if an object 4cm tall is placed 20cm in

front of a concave mirror of focal length 15cm?

A. 60cm                                             

B. 40cm                                             

C. 24cm

D. 12cm                                                         

E. 3cm.

(vi)           What is the main function of step up transformer?

A. To change a.c to d.c current                                                                             

B To decrease resistance in a circuit

C. To increase a.c voltage                                                                     

D To decrease a.c voltage

E. To increase a.c current.

(vii) The most probable radiation forming a well­defined track when passed in a cloud chamber is called

A. Gamma­rays                                               

B. Beta rays                                                      

C. Cathode rays

D. Alpha rays                                                                        

E. X­rays.

(viii) The effect of adding an acceptor impurity to a silicon produce a crystal called 

A. P­type 

B. N­type 

C. PN­type

D. NP­type                                                                                    

E. PNP­type.

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

Because;

 A          Light waves interfere glass prism

 B.       Colours the light.

 C.       In glass different colours travel at different speeds.

 D.      Different colours are filtered

E.       Diffraction of light occurs.

(x)                       Which of the following statements is true when the resistance, R, of a wire
                  is measured using an ammeter, voltmeter and rheostat?

1. The ammeter is in parallel with R
2. The voltmeter is in series with R
3. A graph of V against Ihas a gradient equal to R
4. A graph of Iagainst V has a gradient equal to R
5. The rheostat is in parallel with R.

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) In a light experiment, a narrow beam of light directed onto a glass prism leaves the prism and falls on a a white screen. Draw a labeled 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.                                                         ( 10 marks)

4.     (a) (i)What effect does an increase in temperature have on the density of most liquids?( 1mark)

       (ii) Explain the procedure of using methylated spirit, water and a pendulum bob to   find the relative density of spirit.                                                                                                                                                             ( 2marks)

        (ii) Briefly explain why does a ship sink deeper in fresh water than in sea water?       ( 2marks)

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.                       (3 marks)

5. (a) Define the following terms:

1. Coefficient of superficial expansion.                                                                  (1 mark)
2. Anomalous expansion of water.                                                                          ( 1 mark)

1. (i)How much heat is needed to change 340g of ice at 0°C to water at 0°C?      ( 2marks)             
2. (ii) What is the name of heat lost by ice in (b) (i) above?                                    ( 2marks)

                                                                                                                                                                                                                             radius 8.92mm at 20°C. What temperature must the rivet be heated in order to fit                                         into the hole?                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  ( 4 marks)

               6. (a) (i)State two ways in which the image formed in plane mirror differs from that in a pin hole camera.(2marks)

     (ii) What is the effect of moving the pinhole camera closer to the object?                    ( 1marks)

      (ii) Give two similarities and two differences that exist between the human eye and a lens camera.

( 2marks)

1. A mirage is often seen by a motorist as a pool of water on the road some distance ahead.
2. Draw a sketch diagram to show the formation of such a mirage.               (1mark)
3. Briefly explain how mirage is formed.                                                                          ( 1mark)

            7. (a) (i)What is meant by the internal resistance of a cell?                                                      (1 mark)

                          (ii) Distinguish between a cell and a battery.                                                                          ( 2marks)

         (ii) Identify three disadvantages of a Leclanche cell over a lead­acid accumulators.

                                                                                                                                                   ( 3marks)

1. The current of 3.0A passes through a coil of resistance 5Ω connected to the terminals of a cell of constant e.m.f, E (Volt) and internal resistance, r (ohm). If a uniform wire of length, L (cm) is joined across the ends of a 5Ω coil to form a parallel arrangement of resistance 4Ω , the current is reduced to 0.25A. Determine the
2. internal resistance of a cell.                                                       ( 1 mark)
3. e.m.f of a cell.                                                                             ( 1 mark)

8. (a) (i) Define nuclear fission.                                                                                                ( 1mark)

(ii) Mention two products of nuclear fission.                                                                         ( 2marks)

(b) Figure 1 shows a comparison of the penetrating power of three types of radiations.

Figure 1

1.      Identify the name of radiations represented by the letters A, B and C.                     ( 1 mark)
2. Write two properties of each type of radiation named in 8 (b) (i).                    ( 1 mark)
3. What effect does the radiation B has on the nucleus of an atom?                              ( 1 mark)

 (c) Complete the following equations and for each name the type of decay.

1. ²²⁶88Ra →  --------+ ²²²86Rn .______                                                                                 ( 2marks)
2. ²²²86Rn → 2 −1⁰e +----------------                                                                                                 (2 marks)

SECTION C (25  Marks) 

Answer TWO questions from this section.

9. (a) What is meant by;

1. Asteroids                                                                                                                                ( 2 marks)
2. Astronomy                                                                                                                             ( 2 marks)

(b) Distinguish between the following terms;

1. Constellations                                                                                                                        ( 2 marks)
2. Meteor and meteorites                                                                                                         ( 2 marks)

( c) (i) Mention two tides of tides                                                                                            ( 2 marks)

  (ii) With aid of diagram, describe how ocean tides are formed.                            ( 6 marks)

10. (a) (i) List four main parts of a ripple tank.                                                                     ( 4 marks)

(ii) What role does a stroboscope play in a ripple tank experiment?                                  ( 2 marks)

(ii) What does a violinist do to change the note emitted by a particular string?                ( 1/2 marks)

            (ii)      Calculate the frequency of vibration in a resonance tube of shortest length

of 0.22m when the next resonance length is 0.47m.                                                                         ( 2 marks)

11. (a) (i)State the functions of the hair springs in a moving coil galvanometer.               ( 2 marks)

               (ii) Explain why moving coil galvanometer is unsuitable for measuring alternating currents.

( 2 marks)

(ii) What would happen on the pattern if a.c were used instead of d.c? ( 2 marks)

(ii) An electric motor is connected by cable to a generator and produce a current of 10 A at 240V. Calculate the resistance of the cable.                                                                                       ( 2¹/₂ marks)