Physics Past Questions and Answers

An electron enters perpendicularly into a uniform magnetic field which has a flux density of 0.12 T This results in a magnetic force of 9.6 x 10\(^{-2}\) N on the electron. Calculate the speed of the electron as it enters the magnetic field. (e =1.6 x \(10^{19}\) C)

List three uses of rockets.

(a) What is doping?<br/>(b) Explain how doping improves the conductivity of a semiconductor

The diagram above illustrates a cathode ray tube. Identify the components X, Y, and Z.

(a) Explain the term net force.<br/>(b) Define the principle of conservation of linear momentum and state one example of it.<br/>(c) A ball of mass 200 g released from a height of 2.0 m hits a horizontal floor and rebounds to a height of 1.8 in. Calculate the impulse received by the floor. (g = 10 ms\(^{-2}\)).<br/>(d) A body of mass 20 g performs a simple harmonic motion at a frequency of 5 Hz. At a distance of 10 cm from the mean position, its velocity is 200 cms\(^{-1}\). Calculate its:<br/>(i) maximum displacement from the mean position;<br/>(ii) maximum velocity;<br/>(iii) maximum potential energy. (g = 10 ms\(^{-2}\) \(\pi\) = 3.14)