Question

(a) Distinguish between the terms 'overloading' and 'short-circuiting' as used in domestic circuits.
​(b) Why are the coils of electric toasters made of an alloy rather than a pure metal?

Answer 1

(a) Overloading: When too many electrical appliances of high power voltage are switched on at the same time, a large current from the circuit is drawn. This is called overloading of the circuit. Overloading also occurs due to accidental hike in the supply voltage.

Shortcircuiting: When the live wire and neutral wire come into direct contact, a large amount of current flows through the circuit due to very small resistance, this is called short circuiting. The heat produced during short-circuiting is so high that it may cause a fire.

(b) The coil of the electric toaster is made up of an alloy because alloys have better properties than the pure metals. Such as,

1. They have a high melting point. This is necessary for the electric toaster as it is a heating device.
2. More resistant to oxidation. This is another requirement in a toaster.
3. Mechanically stronger than that of pure metal.