CBSE Class 7 Answered

Hi,

The amount of heat produced in a wire depends on -

(1) Its material – better conductors produce less heat;

Example: Nichrome wire is used for electric appliances whereas connecting wires are made up of copper which is a better conductor so they do not get heated up as the element.

(2) Its length – as length increases heat produced increases.

Example: Elements are coiled in heaters to increase length .

(3) Thickness – as thickness increases heat produced decreases

Example: Lead wires of iron, heater etc. are thicker than normal connecting wire so that they don’t get heated up easily.