The heat produced by a $100\, W$ heater in $2\, minutes$ will be equal to:

If voltage across a bulb rated $220 \text{ V} - 100 \text{ W}$ drops by $2.5\%$ of its rated value,the percentage of the rated value by which the power would decrease is ............... $\%$

The resistance of a device component decreases as the current through it increases and it is described by the relation,$R = \frac{0.2 I}{I-4}$,where $I$ is the current. Determine the minimum power delivered. (Assume $I > 4$) (in $W$)

One kilowatt hour is equal to

An electric lamp is marked $60\, W$, $230\, V$. The cost of $1\, kWh$ of power is Rs. $1.25$. The cost of using this lamp for $8$ hours is Rs. ................

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 ................ $V$.