The resistance of an ideal voltmeter is

$A$ light bulb of resistance $R = 16 \, \Omega$ is attached in series with an infinite resistor network with identical resistances $r$ as shown below. $A$ $10 \, V$ battery drives current in the circuit. Find the value of $r$ in $\Omega$ such that the bulb dissipates about $1 \, W$ of power.

The resistances in the following circuit are $R_1 = R_2 = R_3 = 6.0 \ \Omega$. The emf of the battery is $12 \ V$. When switch $S$ is closed, the potential across resistance $R_1$ changes by an amount:

$A$ network of four resistances is connected to a $9\,V$ battery,as shown in the figure. The magnitude of the voltage difference between the points $A$ and $B$ is .......... $V.$

What is the equivalent resistance of the circuit in $\Omega$?

When a resistance $R_1$ is connected across a cell,the current is $I_1$ and if the resistance $R_1$ is replaced by $R_2$,the current is $I_2$. Then the internal resistance of the cell is