Physics Past Questions and Answers

Explain the action of direct electric current in an electrolytic process with a dilute solution of sodium chloride as electrolyte

(a) What is meant by;
(i) anode;
(ii) cathode, as used in electrolysis?
(b) List the ions involved in an electrolytic process with dilute tetraoxosulphate (VI) acid as electrolyte

(a) Explain how neon signs can be produced.
(b) State two factors on which the colour of light from a fluorescent tube depend.

Explain why a direct electric current is used instead of an alternating current in electroplating.

(a) (i) What is meant by a machine?
(ii) List two examples of a simple machine.
(iii) Explain the statement – the velocity ratio of a machine is 5.
(b) (i) Define the efficiency of a machine.
(ii) Explain why a machine can never be 100% efficient.
(c) A screw jack, 25% efficient and having a screw of pitch 0.4 cm is used to raise a load through a certain height. If in the process, the handle turns through a circle of radius 40.0 cm, calculate the;
(i) velocity ratio of the machine; (ii) mechanical advantage of the machine; (iii) effort required to raise a load of 1000 N with the machine. [Take \(\pi\) =3.14]