Describe, with the aid of a diagram, how a wave can be plane polarized.
State (a) the principle upon which the lightening in fluorescent tubes operate;
(b) two factors on which the colour of light from a fluorescent tube depends.
(a) Define Young modulus of elasticity;
(b) A spiral spring extends from a length of 10.0 cm to 10.01 cm when a force of 20 N is applied on it. Calculate the force constant of the spring.
