# Physics Paper 2 Prediction- Kapsabet Boys

Aug 16, 2022

## SECTION A (25 MARKS)– Kapsabet Boys Physics Paper 2

Answer all the questions in the space provided

1.  Figure 1 below shows a ray of light reflected from a mirror.

Complete the ray diagram and find the new angle of reflection after it is rotated 10 anticlockwise with the incident ray fixed.                                           (2marks)

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2.  Three electric bulbs are connected in series with a battery of two dry cells and a switch. At first the bulbs light brightly.

(a) State a reason why they gradually light dim.                              (2marks)

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(b) The switch is put off for sometimes. Explain why the bulbs again shine brightly.                                                                                           (1mark)

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3.  A positively charged rod is brought near the cap of a lightly charged electroscope. The leaf first collapses and as the rod comes nearer, the leaf diverges.

(i)     What is the charge on the electroscope?                                   (1mark)

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(ii)    Explain the behavior of the leaf.                                                   (2marks)

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4.  Figure 2 below shows a bar magnet attracting steel pin as shown

State and explain what would happen when a North pole of a bar magnet is brought near the tips of steel pin X and Y.                                                          (2marks)

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5.  Determine the equivalent resistance between P and Q for the following resistors shown in Figure 3.                                                             (2marks)

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6.  Figure 4 below shows a wave profile for a wave whose frequency is 5Hz.

Determine the value of t8.                                                                       (2marks)

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7.  An electromagnetic radiation whose wavelength is greater than that of microwaves has a wavelength of 306.1224 m. Take speed of light in air, c = 3 x108 m/s.

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(b) Calculate its frequency.                                                                      (2marks)

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8.  Two heating coils A and B connected in parallel in a circuit produces power of 36W and 54W respectively. What is the ratio of their resistance?(2marks)

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9.  State two conditions necessary for total internal reflection to occur.                                                                                                                                           (2marks)

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10. Define coherent source of a wave.                                                         (1mark)

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11. Figure 5 below show a conductor carrying electric current place between two magnetic poles.

Complete the diagram by sketching the magnetic field and also show the direction of the force on the conductor.                                                         (3 marks)

## Section B (55 marks) – Kapsabet Boys Physics Paper 2

Answer ALL the questions in the spaces provided

12. (a) State one factor that affects the force between two charged bodies.                                                                                                                                (1mark)

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(b) To investigate charge distribution on metallic surfaces, electric charges were collected from different parts of the surfaces using a proof plane as shown in figure 6 below:

The proof plane was then placed on the cap of a neutral electroscope.

(i)        State and explain the leave divergence of the electroscope as the proof plane is placed at various points round the spherical surface in figure (i) above.                                                                                   (2marks)

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(ii)       State with reason which part of the conductor in figure (ii) gave the greatest deflection of the electroscope.                          (2marks)

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(c) Figure 7 shows a 10µF capacitor being charged from a 12V battery by connecting the switch terminal on R. The switch is then connected to S to discharge the 4µF capacitor.

Determine the resultant potential difference between the two capacitors.                                                                                                                           (3marks)

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(c) State two uses of capacitors.                                                            (2marks)

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13. (a) State Faradays law of electromagnetic induction.                     (1mark)

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(b)  Figure 8 below shows a simplified circuit of a generator.

(i)        Identify parts X and Y.                                                                   (2marks)

X: ..…………………………………….

Y: ………………………………………

(ii)       State two ways of making the bulb light brighter.                (2marks)

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(c) An a.c generator produces an e.m.f of 50.0V which is used to operate a circuit that requires a minimum of 250.0V. If the power of the generator is 200W, determine the:

(i) Current generated by the a.c source.                                              (2marks)

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(ii) Current supplied to the circuit by the transformer assuming 100% efficiency.                                                                                                                 (2marks)

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(iii) Ratio of turns in the coils of the transformer, primary: secondary.                                                                                                                                                 (2marks)

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(d) Explain how power loses in a transformer are minimized.                  (2marks)

(i) Eddy currents

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(ii) Hysteresis losses

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14. (a) A disc of a siren with 100 holes is rotated at constant speed making 0.5 revolutions per second. If air is blown towards the holes, calculate:

(i)        The frequency of the sound produced.                                   (2marks)

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(ii)       The wavelength of the sound produced, if the velocity of sound is 340 m/s.                                                                                       (2marks)

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(b) A ship sends out an ultrasound whose echo is received after 5 seconds. If the wavelength of the ultrasound in water is 0.05 m and the frequency of the transmitter is 50 KHz, calculate the depth of the ocean.  (3marks)

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(c) A ray of light is incident at right angles to the face AB, of a right angled isosceles prism of refractive index 1.6 as shown in Figure 8 below.

If the prism is surrounded by a liquid of refractive index 1.40, determine:

(i)        The angle of incidence on the face BC.                                    (1mark)

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(ii) The angle of refraction on the face BC.                                         (3marks)

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15. (a) Distinguish between principal focus and focal length of a concave lens.                                                                                                                             (1mark)

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(b) Figure 9 below shows sketches of a window frame and its image formed on a screen by a convex lens.

(i)        State the nature of the image formed.                                          (2marks)

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(ii)       Calculate the linear magnification of the imaged formed.       (2marks)

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(iii)      The imaged of the frame was produced 500mm from the lens. Calculate the focal length of the lens.                                                                    (3 marks)

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(c) A student finds that at a distance of 25 cm, the words in a book looked blurred.

(i)        What eye defect does the student suffering from?             (1mark)

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(ii)       In which direction does he/she move the book to be able to see the words clearly from the distance?                                               (1mark)

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(iii)      Which lens can be used to correct the eye defect?              (1mark)

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16. (a)  (i) Figure 10 shows a graph of 1/v against 1/u for a concave mirror. Use your graph to determine the focal length of the mirror.              (2marks)

(ii) Determine the image distance when the magnification is m = 2 for the concave mirror above.    (3 marks)

(b)  State one application of each of the following

(i)  Convex mirror.        (1mark)

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(ii) Parabolic mirror.                                                                                 (1mark)

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(c)  A small object is placed 15 cm in front of a convex mirror of focal length 10 cm. Determine the position of the image.                          (3marks)