What is the maximum voltage that can be safely applied across a resistor of $196 \,\Omega - 1 \,W$ rating? .......... $volt$

The ratio of cross-sectional areas of two conducting wires made up of the same material and having the same length is $1 : 2$. What will be the ratio of heat produced per second in the wires,when the same current is flowing in them?

$A$ resistor develops $300 \,J$ of thermal energy in $15 \,s$,when a current of $2 \,A$ is passed through it. If the current increases to $3 \,A$,the energy developed in $10 \,s$ is........$J.$

Two wires '$A$' and '$B$' of the same material have lengths in the ratio $1 : 2$ and radii in the ratio $2 : 1$. If the two wires are connected in parallel to a battery,the ratio of heat produced in wire '$A$' to that in wire '$B$' will be:

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 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. ................