When the power delivered by a $100\,V$ battery is $40\,W$,the equivalent resistance of the circuit is ........... $\Omega$.

$A$ room heater is rated $400 \text{ W}$, $220 \text{ V}$. If the supply voltage drops to $200 \text{ V}$, what will be the power consumed (approximately) (in $\text{ W}$)?

Heat is produced at a rate given by $H$ in a resistor when it is connected across a supply of voltage $V$. If now the resistance of the resistor is doubled and the supply voltage is made $V / 3$,then the rate of production of heat in the resistor will be

Which of the following statements is false?

What is the ratio of heat generated in resistors $R$ and $2R$ connected in parallel as shown in the figure?

$A$ heater of $220\, V$ heats a volume of water in $5\, \text{min}$ time. $A$ heater of $110\, V$ heats the same volume of water in ............... $\text{min}$.