Physics Past Questions and Answers

(a) (i) Define relative density.
(ii) List three characteristics of pressure in a liquid.
(b) The horizontal door of a submarine at a depth of 500m has an area of 0.4m\(^{2}\). Calculate the force exerted by the sea water on the door at this depth. [Relative density of sea water = 1.03 ] [Atmospheric pressure =- 1.01 x 10\(^{5}\) Nm\(^{-2}\)] [Density of pure water = 1000kgm\(^{-3}\)] [g = 10ms\(^{-2}\)]
(c) (i) List three effects of heat other than expansion.
(ii) Explain saturated vapour pressure.
(iii) A heating coil of resistance 20 \(\Omega\) connected to a 220 V source is used to boil a certain quantity of water in a container of heat capacity 100 J kg\(^{-1}\) for 2 minutes. If the initial temperature of the water is 40° C, calculate the mass of the water in the container. [specific heat capacity of water = 4.2 x 10\(^3\) Jkg\(^{-1}\) K\(^{-1}\)] [assume boiling point of water = 100°C]

(a) State Heisenberg's uncertainty principle
(b) mention two phenomena that can only be explained in terms of the particulate nature of light

(a) Define the following terms as applied to a convex mirror:
(i) principal focus; (ii) pole (iii) radius of curvature.
(b) State one advantage and one disadvantage of using a convex mirror as a driving mirror.
(c) Draw a clearly labelled diagram to illustrate how two converging lenses may be arranged to form a compound microscope.
(d) An object 2.5 mm long is viewed through a converging lens of focal length 10.0 cm held close to the eye. A magnified image of the object is formed 30.0 cm from the lens. Calculate the:
(i) distance of the object from the lens; (ii) size of the image; (iii) power of the lens.

(a) Define: (i) reactance; (ii) impedance.
(b)(i) Explain resonant frequency of an RLC circuit.
(ii) Explain the statement – the power supply voltage of a source is 230V
(c) A source of e.m.f 240V and frequency 50 Hz is connected to a series arrangement of a resistor, an inductor and a capacitor. When the current in the capacitor is 10A, the potential difference across the resistor is 140 V and that across the inductor is 50 V. Calculate the:
(i) potential difference across the capacitor (ii) capacitance of the capacitor; (iii) inductance of the indicator.
(d) Draw and label one vector diagram for the potential differences across the inductor, the capacitor and the resistor in (c) above.

A force of 6N acts horizontally on a stationary mass of 2kg for 4s. The kinetic energy gained by the mass is _________