CBSE 2024 · Region 2 · Set 1 · Q39

When electric current flows in a purely resistive circuit electrical energy gets fully converted into heat energy. The amount of heat produced (H) in the circuit is found to be directly proportional to (i) the square of current $\displaystyle \left(\mathrm{I}^{2}\right)$ (ii) the resistance (R) of the conductor and (iii) the time (t) for which current flows. In other words $\displaystyle \mathrm{H}=\mathrm{I}^{2} \mathrm{Rt}$. Electrical devices such an electric fuse, electric heater, electric iron etc. are all based on this effect called heating effect of electric current.

(a)

List two properties of heating elements.

(b)

List two properties of electric fuse.

(c)OR(c)

Name the principle on which an electric fuse works. Explain how a fuse wire is capable of saving electrical appliances from getting damaged due to accidently produced high currents.