How many units are consumed if a $100\,W$ electric bulb is kept $ON$ for $10$ hours?

An electric bulb rated $50 \, W-200 \, V$ is connected across a $100 \, V$ supply. The power dissipation of the bulb is: (in $ \, W$)

The energy consumed in a $1\, kW$ electric heater in $30$ seconds will be:

Water boils in an electric kettle in $20$ minutes after being switched on. Using the same main supply,the length of the heating element should be . . . . . . to . . . . . . times of its initial length if the water is to be boiled in $15$ minutes.

How many calories of heat will be produced approximately in a $210\, W$ electric bulb in $5$ minutes?

An electric bulb of $100\, W$ is connected to a supply of electricity of $220\, V$. The resistance of the filament is ............. $\Omega$.