State the conditions under which a body remains in equilibrium when acted upon by parallel coplanar forces. What is meant by (i) Stable equilibrium (ii) Unstable equilibrium (iii) Neutral equilibrium?

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What do you understand by the term ECHO? List four factors which affect the pitch of a note given by a stretched string. The frequency obtained from a plucked string is 400 Hz when the tension is 2N. Calculate its frequency when the tension is increased to 8N.

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Explain how an ebonite rod rubbed with fur acquires a negative charge. With the aid of a well labelled diagram, explain how you would use an ebonite rod and fur to charge a gold-leaf electroscope, positively.

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State Hooke's law for a material in the form of a wire or rod. Draw a load-extension graph for a wire made of (i) a ductile material (ii) a brittle material Point out the main features shown by each curve.

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Define "The Principal Focus of a lens." An object is placed 20cm from a converging lens. An image is found 60cm on the other side of the converging lens. What is the focal length of this lens? A rectangular tank 5m deep is full of water. By how much does the bottom appear to be raised if the refractive index of water is 1.33?

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Draw Rutherford-Bohr models of the three hydrogen isotopes. Write the name of the particle represented by each of the following symbols. (i) $\frac{1}{0}n$ (ii) $-1^0e$

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Define

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Draw a diagram of a dry cell and label the 8 main parts. Briefly explain why iron screws are never used on ships to fasten copper fittings exposed to salty water.

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When does thermionic emission of electrons occur? The radium nucleus, 226Ra decays to radon (Rn) by α- particle emission. Write the nuclear equation for this change. Write the nuclear equation for the change of a radio-isotope of sodium, 24Na which emits β - particles and turns into magnesium.

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Briefly explain how a transformer works. Giving reasons, explain why you would expect the efficiency of a transformer to be less than 100%.

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What is a voltameter? A steady current of 2A flows through a copper voltameter. Find the thickness of the layer of copper deposited uniformly on the electrode of surface area 40cm² in 30 minutes. (Density of copper = 9000kg/m³; Mass of copper deposited per coloumb = 3.3 x 10⁻⁷kg/C.)

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What is meant by the "absolute zero temperature"? State Charles' law. Using Charles' law, show graphically how the volume of a given gas varies with temperature. To what temperature must 2 litres of a gas at 17⁰C be heated at constant pressure in order to increase its volume to 3 litres?

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What is meant by each of the following terms? Name the three classes of levers. How is the efficiency of a machine related to its velocity ratio and mechanical advantage? A fitting tackle has three pulleys in each block. What is its velocity ratio? What was the total effort required to raise a load of 24kg? What was the mechanical advantage of the tackle?

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Define "wave intensity" and state the "inverse square law" for electromagnetic radiation in free space. Given the following types of magnetic radiations: ultra-violet, gamma rays, radio waves. State which of the radiations has the Calculate the frequency of a radio wave whose length is 300m.

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Use the above circuit diagram to calculate the (i) current flowing through the battery (ii) potential difference (p.d.) across the 4Ω resistor.

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A man determines the width of a dam by using a steamer sailing in the dam. The man sees a stream from the steamer's whistle, 3 minutes later he hears the whistle and 4 seconds after that he hears an echo from a high wall directly behind the steamer. What is the width of the dam? (Velocity of sound in air = 330m s⁻¹)

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An electric kettle contains a heating unit operating on 240V main and carrying a current of 4 amperes. Calculate the power consumed by the heating unit.

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