PHYSICS QUIZ 9 O' LEVEL

PHYSICS QUIZ 9 O' LEVEL

1. . (a) Define resistivity and conductivity as referred to in electricity.
(b) Two wires A and B are made of the same material. A has half the length and twice the diameter of B. What is the ratio of the resistance of B to that of A?

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2. (a) Draw a labeled diagram of a simple d.c. motor.
(b) Explain why the coil will rotate when the current flows in it and why it will turn in a specific direction.
(c) Why does such a motor occasionally not start to rotate when the current is switched on but will give continuous rotation after a slight push?

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3. (a) State one way in which cathode rays differ from electromagnetic waves and describe an experiment that illustrates this difference.
(b) Draw a labeled diagram of a longitudinal section view of the cathode ray oscilloscope tube showing its main features.

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4. (a) What are asteroids?
(b) Distinguish between:
(i) a planet and a star (ii) a comet and à meteor
(c) Name three planets that are closest to the sun.

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5.(a) Define vaporization and specific latent heat of vaporization of substance.
(b) How much heat is given up when 4 grams of steam at 100°C condenses to water at 4°C?

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