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The chart below shows part of the electromagnetic spectrum.
(a) Identify the radiation marked A and C.
(b) Give one application of the radiation marked B.
Date posted:
September 6, 2019
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The figure below shows a steel bar to be magnetized.
Complete the circuit such that both poles P and Q acquire opposite polarity (North- south respectively).
Date posted:
September 6, 2019
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An object of height 2 cm is placed 25 cm in front of a concave mirror. A real image is formed 75 cm from the mirror.Calculate the height of the image.
Date posted:
September 6, 2019
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The figure below shows a ray of light incident on a plane mirror.
(a) On the diagram, indicate the direction of the reflected ray.
(b) Give a reason for the path shown above.
Date posted:
September 6, 2019
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A certain mass of hydrogen gas occupies a volume of 1.6m3 at a pressure of 1.5x105Pa and a temperature of 120c. Determine the volume when the temperature is 00c at a pressure of 1.0x103
Date posted:
September 6, 2019
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A cork of volume 100cm3 is floating on water. If the density of the cork is 0.25 gcm-3 and that of water is 1 gcm-3;
(a) Calculate the mass of the cork
(b) Hence, find the upthrust force on the cork
(c) What minimum force is required to immerse the cork completely
(d) What is the effect on the upthrust force in a liquid when the temperature of the liquid is reduced?
Date posted:
September 6, 2019
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In an experiment to determine the specific latent heat of vaporization of water, steam at 100ºC was passed into water contained in a well-lagged copper calorimeter. The following measurements were made:
- Mass of calorimeter = 60g
- mass of water + calorimeter = 145g
- Final mass of calorimeter + water + condensed steam = 156g
- Final temperature of the mixture = 48oC
[Specific heat capacity of water = 4200JKgˉ¹kˉ¹ and specific heat capacity of copper = 390JKgˉ¹kˉ¹
Determine the;
(i) mass of condensed steam.
(ii) The heat gained by the water and calorimeter if the initial temperature of the calorimeter and water is 20ºC.
(iii) Given that Lv is the specific latent heat of vaporization of steam, write an expression for the heat given out by steam.
(iv) Determine the value of Lv above
(v) State the assumption made in the above experiment
Date posted:
September 6, 2019
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The diagram below shows a graph of force against extension for a certain spring.
(i) What is the spring constant of the spring?
(ii) What force would cause two such springs placed side by side to stretch by 10cm
Date posted:
September 6, 2019
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The height of a mountain is 1360m. The barometer reading at the base of the mountain is 74cmHg. Given that the densities of mercury and air are 13,600Kgm-3 and 1.25Kgm-3 respectively, determine the barometer reading at the top of the mountain.
Date posted:
September 6, 2019
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The figure below is a simple hydraulic machine used to raise heavy loads.
Calculate;
(i) The pressure exerted on the oil by the force applied at A
(ii) The load raised at B
(iii) Give two properties which make the oil suitable for use in this machine
Date posted:
September 6, 2019
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A stone of mass 40g is tied to the end of a string 50cm long such that it is 20m above the ground at its lowest level as shown in the diagram below. It is whirled in a vertical circle at 2rev/s.
(i) If the string breaks at its lowest level as shown, what is the velocity with which it travels?
Calculate the maximum tension in the string.
(ii) Calculate the maximum tension in the string.
(iii) Determine the maximum horizontal distance it travels from the breaking point
Date posted:
September 6, 2019
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Using Kinetic theory of matter, explain why solids expand when heated.
Date posted:
September 6, 2019
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The figure below shows a machine being used to raise a load.Determine the efficiency of the machine.
Date posted:
September 6, 2019
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The diagram below shows a braking system.Why is the master piston, made smaller than the slave piston?
Date posted:
September 6, 2019
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The diagram below shows a uniform 5m long metal rod of mass 800g. It is suspended by a string tied at a point 3.5m from one end. Determine the load which should be hung at point X to keep the plank horizontal.
Date posted:
September 6, 2019
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A tube of radius 9 mm has a constriction of diameter 10mm. Water flows in the tube at 3m/s. Determine the velocity of water in the constriction.
Date posted:
September 6, 2019
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The diagram below shows a micrometer screw gauge. What is the reading in SI units?
Date posted:
September 6, 2019
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A cell supplies a current of 0.5A when connected to a 2 ohms resistor and 0.25A when connected to a 5 ohms resistor. Find the e.m.f and the internal resistance of the cell.
Date posted:
September 6, 2019
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The figure shows three resistors as shown.If the voltmeter reads 4V, find the
(i) Effective resistance
(ii) Current through the 3 ohms resistor
(iii) Potential difference across the 8 ohms resistor.
Date posted:
September 6, 2019
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Define electric resistance.
Date posted:
September 6, 2019
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The figure below shows photocell used in a set-up for a burglar alarm.
(i) Give a reason why the photocell is usually evacuated.
(ii) State the function of the resistor R in this circuit
(iii) Explain why a particular radiation such as ultra-violet light is used to strike a given cathode surface.
(iv) Explain how the set-up in the figure can be used as a burglar alarm.
Date posted:
September 6, 2019
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The figure below illustrates a method of charging a metal sphere.
(i) Name the method of charging shown in the figure.
(ii) Indicate the final charge on the sphere in the figure.
Date posted:
September 6, 2019
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In an experiment to investigate factors affecting capacitance of a capacitor, a student increased the area of the plates and decreased the separation of the plates. Explain the effect on the capacitance when
(i) the area of plates increased
(ii) the distance of the separation of the plates decreased
Date posted:
September 6, 2019
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A converging lens forms an image which is three times the object. Determine the focal length of the lens if the distance between the object and the screen is 80cm.
Date posted:
September 6, 2019
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The graph below shows the variation of 1/v and 1/u in an experiment to determine the focal length of a lens.
(i) Use the graph to determine the focal length
(ii) What is the power of the lens used?
Date posted:
September 6, 2019
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An optician in Eldoret Hospital examined an eye of a patient and made the following observations:
Eye too short and the focal length of the eye lens short
(i) State the eye defect the patient could be having.
(ii) Use a diagram to describe how the defect could be corrected.
Date posted:
September 6, 2019
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Some students wish to determine the focal length of a convex lens of thickness 0.6cm using an optical pin and a plane mirror.The figure shows the experimental set up when there is no parallax between the pin and the image.
Determine the focal length of the lens.
Date posted:
September 6, 2019
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Below is part of a circuit that was setup by form four students of Okok Seconday School during a physics practical lesson to demonstrate full wave rectification using two diodes. Complete the circuit by correctly placing the load R and two diodes.
Date posted:
September 6, 2019
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A sample of a radioactive substance initially has 8.0 x 1025 particles. The half life of the sample is 98 seconds. Determine the number of particles that will remain after 294 seconds.
Date posted:
September 6, 2019
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A form two student from Kimomo Secondary School found his dry cells leaking on removing from his torch. What would be the possible cause of the leakage?
Date posted:
September 6, 2019