A ray is incident on two mirrors inclined at 600 as shown in the diagram below.

Determine the angle of reflection on mirror B, hence trace the path of the ray as it leaves mirror B.

State and explain the observation made when an acetate rod rubbed with fur is brought close to the
cap of a negatively charged electroscope.

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State how polarization is reduced in a dry cell.

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Distinguish between a P-type and a N-type extrinsic semiconductors.

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State one similarity and one difference between the gamma rays and x-rays based on the mode of
generation of the radiations.
i) Similarity (1mk)
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ii) Difference (1mk) …..………………………………………………………………………………………………………
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X-rays are produced by a tube operating at 104 Volts. Calculate the wavelength of the radiation.
(Take h=6.63x10-34Js, e=1.6x10-19C, c =3x108m/s)

State how a vertical trace can be obtained on the screen of a cathode ray oscilloscope.

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A boat sends a sound signal in the middle of Lake Victoria and an echo is heard after 6 seconds.
Determine;
i) The depth of the lake. (2mks)
ii) The frequency of the signal stated in (i) above. (1mk)
(Take speed of sound in water = 1440ms^-1, wavelength = 0.4m)

A concave mirror produces an erect image of magnification 2. If the focal length of the concave
mirror is 30cm, find the distance of the object from the mirror.

(Hint: the image is virtual)

State Lenz’s law of electromagnetic induction.

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The coils P and S are connected as shown below. P is connected to a battery, rheostat and a switch
K. S is connected to a galvanometer G.

State the behaviour of the pointer on G in the following cases;
i) When K is switched on (closed) (1mk)

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ii) When K is opened. (1mk)

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A current of 5mA passes through a wire of length 1.0m, radius 1.0x10^-4 mm and resistivity
1.1x10^-6Ωm. Calculate the rate at which heat is given off by the wire. (Assume temperature is
constant.)

a) Define the term photoelectric effect. (1mk) …..………………………………………………………………………………………………………
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b) The diagram below shows a circuit to investigate the photoelectric effect using a photocell.
i) Explain why the milliameter shows a reading when ultraviolet light is shone as in the diagram.
(3mks)

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ii) State with a reason how the milliameter reading is affected when the intensity of light is increased.
(2mks)

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iii) State one practical application of a photocell.

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c) A laser beam of intensity 2x10^-1Nm^-2 and wavelength =5x10^-7m hits a wall 5m away. How many
photons per second are emitted? (3mks)
(Take h=6.6x10^-34Js, c=3x108ms^-1)

a) Differentiate between a nuclear fussion and nuclear fission. (2mks)

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b) The equation below represents a nuclear reaction.
i) Determine the values of p and q. (1mk)
p………………………………..………………………..

q…………………………………..……………………..

ii)Identify Y…………………………………………………………………....……. (1mk)
c) The figure below represents deflection of various radiations from a radioactive source S placed in
electric field between two plates X and Y.

Identify the radiations marked with letters M and P. (1mk)
M…………………………………………………………………………………
P……………………………………………………………………………………
d) What do you understand by the term ‘Random decay’ (1mk) …..………………………………………………………………………………………………………
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e) A sample of radioactive substance initially has 8x10²⁵ particles. The half life of the sample is 98
seconds. Determine the number of particles that will have decayed after 294 seconds. (3mks)

a) State Snell’s law. (1mk) …..………………………………………………………………………………………………………
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b) Find the angle of incidence of a ray of light on one phase of a 600 prism if the ray is just totally
internally reflected on meeting the next face. (3mks)
(Take refractive index of glass = 1.5)
c) Explain why glass prisms are preferred for use in periscopes to plane mirrors. (1mk) …..………………………………………………………………………………………………………
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d) i) State two ways in which a photographic camera is different from the human eye. (2mks) …..………………………………………………………………………………………………………
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ii) Determine graphically in the space below the position, size and nature of the image of an object
2cm high placed 30cm away from a diverging lens of focal length 20cm. (5mks)
(Use the scales vertically: 1cm rep 1cm, horizontally: 1cm rep 10cm)

a) Differentiate between a transverse wave and a longitudinal wave. (2mks) …..………………………………………………………………………………………………………
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b) Water ripples are caused to travel across the surface of a shallow tank by means of a suitable
straight vibrator.
The distance between successive crests is 3.0cm and the waves travel 25.2cm in 1.2s.

Calculate:
i) The velocity of the waves. (2mks)
ii) The frequency of the vibrator. (3mks)

a) State any two disadvantages of direct transmission of electricity from power generating stations at
a large current through the transmission cables. (2mks)
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b) The diagram below represents part of a domestic wiring system.

i) Identify any two mistakes in the wiring above and explain how they should be corrected. (4mks) …..………………………………………………………………………………………………………
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ii) Identify the circuit H represented above. (1mk) …..………………………………………………………………………………………………………
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c) Complete the wiring to the socket in the wiring system H above. (1mk)

a) The figure below represents a circuit diagram of three resistors connected to a 12V battery.

Determine;
i) The effective resistance for the arrangement above. (2mks)
ii) The potential difference across the 3 Ω resistor. (3mks)
b) The figure below shows part of the circuit containing two capacitors C1 and C2.

If C1=2F and the Pd across PQ is 150V while the total charge in the capacitors is 1.8x10^-4
coulombs. Determine the capacitance of C2. (4mks)​