In an experimental set$-$up as shown below, a piece of silver was placed touching points $A$ and $B .$ Next time it was replaced by a piece of wood. In which case did the bulb glow ? Give reason to justify the observation.
What is the resistance of an electric arc lamp, if the lamp uses $20\, A$ when connected to $220$ volt line ?
The resistivity of all pure metals increases with increase in temperature.
How much work is done in moving a charge of $2$ coulomb from a point at $118$ volt to a point at $128$ volt ?
Given reason for the following
$(i)$ Tungsten used almost exclusively for filament of electric lamp.
$(ii)$ Why do we use copper and aluminium wires for transmission of electric current ?