$A$ lamp of $60 \, W, 230 \, V$ is used for $8 \, \text{hours}$. If the cost of $1 \, \text{unit}$ is $1.25 \, \text{Rs}$, what will be the total bill in $Rs$?

$A$ current $i$ passes through a wire of length $l$, radius of cross-section $r$ and resistivity $\rho$. The rate of heat generation is

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:

$A$ heater coil is cut into two parts of equal length and one of them is used in the heater. The ratio of the heat produced by this half coil to that by the original coil is

$A\, 5\, ^oC$ rise in the temperature is observed in a conductor by passing some current. When the current is doubled,then the rise in temperature will be equal to ............. $^oC$.

According to Joule's law,if the potential difference across a conductor having a material of specific resistance remains constant,then the heat produced in the conductor is directly proportional to