The value of the resistance $R$ in the figure is adjusted such that the power dissipated in the $2\,\Omega$ resistor is maximum. Under this condition:

Electroplating does not help in

The potential difference across the $100\,\Omega$ resistance in the following circuit is measured by a voltmeter of $900\,\Omega$ resistance. The percentage error made in reading the potential difference is

Which of the following graphs represents the variation of power loss in the external load with external resistance $R$?

$A$ wire of resistance $10\, \Omega$ is bent into a circle. $P$ and $Q$ are two points on the circumference of the circle that divide the circle into a quadrant. When these two points are connected to a battery of $3\, V$ and internal resistance $1\, \Omega$, the currents passing through the two parts of the circle are:

$A$ wire of length $L$ and $3$ identical cells of negligible internal resistances are connected in series. Due to current,the temperature of the wire is raised by $\Delta T$ in a time $t$. $A$ number $N$ of similar cells is now connected in series with a wire of the same material and cross-section but of length $2L$. The temperature of the wire is raised by the same amount $\Delta T$ in the same time $t$. The value of $N$ is