Physics Past Questions and Answers

(a) What is meant by dispersion of white light?
(b) State the colours in the spectrum of white light in ascending order of their wavelengths
(c) Which colour is deviated.
(i) least
(ii) most?
(d) Explain why white light is dispersed when it passes through a glass prism.
(e) Describe, with the aid of a labelled diagram, how a pure spectrum of white light can be produced on a screen.

(a) Explain what is meant by the statement: The capacitance of a parallel-plate capacitor is 2\(\mu\)F
(b) State: (i) three factors on which its capacitance depends
(ii) three uses of capacitors.
(c) Derive a formula for the energy W stored in a charged capacitor of capacitance C carrying a charge Q on either plate.,
(d) Two parallel-plate capacitors of capacitances 2\(\mu\)F and 3\(\mu\)F are connected in parallel and the combination is connected to a 50V d.c. source. Draw the circuit diagram of the arrangement and determine the:
(i) charge on either plate of each capacitor
(ii) potential difference across each capacitor
(iii) energy of the combinad capacitors.

An object of mass 0.40 kg attached to the end of a string is whirled around in a horizontal circle of radius 2.0m with a constant speed of 8\(ms^{-1}\). Calculate the angular velocity of the object

An object of mass 0.40 kg attached to the end of a string is whirled around in a horizontal circle of radius 2.0m with a constant speed of 8\(ms^{-1}\). Calculate the angular velocity of the object

An object falls freely from a height of 25m onto the roof a building 5m high. Calculate the velocity with which the object strikes the roof (g=10\(ms^{-2}\)