Physics Past Questions and Answers

A light wave travels from air into a medium of refractive index 1.54. If the wavelength of the light in air is \(5.9\times10^{-7}\)m, calculate its wavelength in the medium

The density of a body is \(5\times10^3kgm{^-3}\) and it weighs 1N in air. Calculate the apparent weight of the body when totally immersed in water. (Density of water =\(10^3kgm{-3}, g= 10ms^{-2}

The density of water is 1g\(cm^3\) while that of ice is 0.9\(cm^3\), calculate the volume change when 90g of ice is completely melted

(a) What is meant by the statement: The specific heat capacity of copper is \(400 J kg^{-1}K^{-1}\)?
(b)(i) Describe an experiment to determine the specific heat capacity of copper using a copper ball.
(ii) State two precautions necessary to obtain accurate results
(iii) A piece of copper ball of mass 20 g at 200°C is placed in a copper calorimeter of mass 60 g containing 50 g of water at 30°C, ignoring heat losses, calculate the final steady temperature of the mixture (Specific heat capacity of water = \(4.2 J g^{-1}K^{-1}\)) (Specific heat capacity of copper = \(0.4 Jg^{-1}K^{-1}\)).

(a) Describe an experiment to show how the frequency of the note emitted by a vibrating string depends on the tension in the string
(b) Draw diagrams showing a vibrating string fixed at both ends emitting (i) fundamental frequency (ii) second overtone indicate the nodes and antinodes on the diagrams
(c) With the aid of a ray diagram show how a virtual image of an object is formed by a (i) concave mirror (ii) converging lens