When a current flows through a wire of resistance $R$ under a constant potential difference,the heat produced by the current is inversely proportional 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 ............... $\%$

If voltage across a bulb rated $220 \,V, 100 \,W$ drops by $2.5 \%$ of its rated value, then the percentage of the rated value by which the power would decrease is (in $\%$)

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

$A$ piece of fuse wire melts when a current of $15\, A$ flows through it. With this current,if it dissipates $22.5\, W$,the resistance of the fuse wire will be .............. $\Omega$.

$A$ hot electric iron has a resistance of $80\,\Omega$ and is used on a $200\,V$ source. The electrical energy spent,if it is used for two hours,will be ........... $Wh$.