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The figure below shows a circuit diagram for a photocell.
i) Explain why the milliammeter shows a deflection when ultraviolet light is shone on the photocell.
ii) Explain how the milliammeter reading is affected when the intensity of UV light is increased.
Date posted:
May 29, 2019
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The figure below shows four capacitors connected to a battery of 12 volts.
Calculate :
i) effective capacitance.
ii) charge on the capacitor of 3.2
iii) p.d across the capacitor of 5
iv) the energy stored by the capacitor of 2
Date posted:
May 29, 2019
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A student while investigating the focal length of a certain concave mirror, measured object and image distances
and drew a graph of 1/u against 1/v shown below.
From the graph, determine the focal length.
Date posted:
May 29, 2019
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What is meant by the term “topping” as applied to a lead acid accumulator ?
Date posted:
May 29, 2019
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The figure below shows a ray of light XY striking the mirror CD held at an angle of 1080 to mirror DE.
Complete the path of the ray XY and state the final angle of reflection.
Date posted:
May 29, 2019
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The maximum wavelength of light required to cause photoelectric emission on a metal surface is 8.0×10-7. The metal surface is irradiated with light of freque4ncy 8.5 × 1014 Hz. Determine
i) The threshold frequency.
ii) The work function of the metal in electron volts.
iii) The maximum kinetic energy of the electron.
iv The maximum velocity of the emitted electrons.
(Take 1ev = 1.6×10-19J, C=3.0×108m/s, h=6.63×10-34Js and mass of electron = 9.11 × 10-31kg)
Date posted:
May 27, 2019
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The diagram below shows a magnetic material being magnetised.
Sketch a graph of magnetic strength against number of strokes for the material being magnetised on the grid below.
Date posted:
May 27, 2019
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Calculate the angle of refraction for a ray of light incident to an air-glass interface, making an angle of a 50° with the interface.
Date posted:
May 27, 2019
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A gun is fixed upwards from the top of an open truck moving horizontally at a uniform velocity of 50m/s, the bullet achieved a maximum height of 45 m.
i) State with reason whether or not the bullet will land on the truck.
ii) Calculate the distance covered by the truck just before the bullet reached the same level from which it was fired.
Date posted:
May 27, 2019
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A simple hydrometer is made using a flat base test tube of mass 15g and length 12cm. The test tube is partly filled with lead shots. Given that the test tube has a uniform cross section are of 2.0cm² and 10cm of its length is under water. Calculate
i) The mass of the lead shots in the test tube.
ii) The length of the test tube immersed if placed in brine which has a density of 1.25g/cm³
iii) The lowest density of liquid in which this test tube would float.
Date posted:
May 27, 2019
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The diagram below shows a wooden block of dimensions 50cm by 40cm by 20cm held in a position by a string attached to the bottom of a swimming pool.
i) The three forces acting on the block are the tension (T) in the string, the weight (W) of the block and the upthrust (U) due to water.
Write an equation relating T, W and U when the block is at stationary.
ii) What is the weight of the block.
iii) What is the weight of the water displaced by the block.
iv) Determine the tension (T) on the string. (density of the block is 600kgm-3; density of water is 1000kgm-3)
Date posted:
May 27, 2019
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In the diagram below, find the pressure of the air in the tube X in the mmHg. The liquid shaded is mercury and the atmospheric pressure is 760mmHg.
Date posted:
May 27, 2019
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The paddle wheel in the diagram below is made of a light material and fixed on a well oiled pivot.
What will happen to the wheel when water is being heated?
Date posted:
May 27, 2019
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Name and explain the features that make a retort stand stable.
Date posted:
May 27, 2019
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Arrange the following electromagnetic waves in order of their increasing wavelengths.X-rays, Gramma rays, Ultraviolet, Visible light, Microwaves, Infra red.
Date posted:
May 27, 2019
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The waves have a speed of 0.12 m/s in the deep water. Wave crests are 0.08 apart to the deep water. Calculate the frequency of the source producing the waves.
Date posted:
May 27, 2019
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You are provided with two identical cells. Two lamps and a switch.
(i) Draw a circuit diagram that would ensure that the bulbs have maximum brightness.
(ii) State one advantage of using such an arrangement in (i) above to light a whole house with many bulbs.
Date posted:
May 27, 2019
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Two springs of negligible weight of spring constant K1 = 24 N/m and K2 = 48 N/m respectively
are connected end to end and suspended from a fixed point as shown below.
Determine;
I the total extension when a mass of 1.2 kg is hung from the lower end.
II the constant of the combination
Date posted:
May 27, 2019
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A ball is thrown horizontally at 8m/s from the tower. It reaches the ground after 4 seconds.Calculate the height of the tower.
Date posted:
May 27, 2019
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The figure below shows a micrometer screw gauge used to measure the diameter of a metal rod. When the rod is removed and the jaws of the gauge are closed the reading is 0.14 mm. Determine the diameter of the rod.
Date posted:
May 27, 2019
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A transformer with 2000 turns in the primary circuit and 150 turns in the secondary circuit has its primary circuit connected to a 800V a.c source. It is found that when a heater is connected to the secondary circuit, it produced heat at the rate of 1000W. Assuming 100% efficiency, determine the;
i) Voltage in the secondary circuit.
ii) Current in the primary circuit.
iii) Current in the secondary circuit.
iv) State the type of transformer represented above.
Date posted:
May 25, 2019
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An electric heater is found to have a resistance of 950Ω when operating normally on a 240V mains. Find the power rating of the heater.
Date posted:
May 25, 2019
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Figure below shows a ray of light incident along the normal. The mirror is rotated at an angle of 15o in a clockwise direction without changing the position of the incident ray,
Determine the angle between the reflected ray and the incident ray.
Date posted:
May 25, 2019
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A balloon weighs 10N and has a gas capacity of 2m3. The gas in the balloon has a density of 0.1kg/m3.
If density of air is 1.3kgm-3, calculate the resultant force of the balloon when it is floating in air.
Date posted:
May 25, 2019
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A piece of sealing wax, weight 3N in air and 0.22N when immersed in water, calculate the density of the wax.
Date posted:
May 25, 2019
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A glass capillary contains enclosed air by a thread of mercury 15cm long when the tube is horizontal, the length of the enclosed air column is 24cm as shown.
(i) What is the length of the enclosed air column when the tube is vertical with the open end uppermost if the atmospheric pressure is 750mmHg?
(ii) What is the length of the enclosed air column when the tube is vertical with the closed end upper most if the atmospheric pressure is 750mmHg.
(iii) Explain why the mercury does not run out when the tube is vertical with the closed end uppermost.
Date posted:
May 25, 2019
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The figure below shows an inclined plane, a trolley of mass 60kg being pulled up the slope by a force of 200N parallel to the slope. The trolley is moved from X to Y.
Determine the
(i) Work output of the system.
(ii) Work input of the system.
(iii) The frictional force between the wheels of the trolley and the inclined plane.
(iv) The efficiency of the system.
(v) The velocity ratio of the system.
Date posted:
May 25, 2019
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When the flask is placed in iced water the level on water rose and then fell. Explain this observation.
Date posted:
May 25, 2019
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An aircraft 300m from the ground traveling horizontally at 400m/s releases a parcel. Calculate the horizontal distance covered by the parcel from the point of release.(Ignore air resistance).
Date posted:
May 25, 2019
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Sketch a velocity – time graph for a body initially moving at a velocity u before a force F is applied to it for 5 seconds and there after the force F is withdrawn.
Date posted:
May 25, 2019