A steady current $I$ flows through a wire of radius $r$, length $L$ and resistivity $\rho$. The current produces heat in the wire. The rate of heat loss in a wire is proportional to its surface area. The steady temperature of the wire is independent of
$L$
$r$
$I$
$\rho$
A torch bulb rated as $4.5\, W, 1.5\, V$ is connected as shown in the figure. The $e.m.f.$ of the cell needed to make the bulb glow at full intensity is ............. $V$
If $2.2\, Kwatt$ power is transmitted through a $10\, ohm$ line at $22000\, volt$, the power loss in the form of heat will be ............. $watt$
On an electric heater $220\, volt$ and $1100\, watt$ are marked. On using it for $4$ hours, the energy consumed in $kWh$ will be
Wheat stone bridge is balanced. Find ratio of electric power dissipated in $(P + Q)$ to $(R + S)$
In the circuit shown, the resistance $r$ is a variable resistance. If for $r = fR,$ the heat generation in $r$ is maximum then the value of $f$ is