For driving a current of $2\, A$ for $6$ minutes in a circuit, $1000\, J$ of work is to be done. The $e.m.f.$ of the source in the circuit is ................ $V$.

In a large building,there are $15$ bulbs of $40\ W$,$5$ bulbs of $100\ W$,$5$ fans of $80\ W$,and $1$ heater of $1\ kW$. The voltage of the electric mains is $220\ V$. The minimum capacity of the main fuse of the building will be ................ $A$.

An electric fan and a heater are marked as $100 \ W, 220 \ V$ and $1000 \ W, 220 \ V$ respectively. The resistance of the heater is

When two electric bulbs of $40\, W$ and $60\, W$ are connected in parallel,then:

There are four bulbs of power $100 \,W, 200 \,W, 500 \,W$ and $1000 \,W$. Among these, which filament has the highest resistance? (Assuming the same voltage source)

An electric bulb marked $40\, W$ and $200\, V$,is used in a circuit of supply voltage $100\, V$. Now its power is (in $, W$)