All wires have the same resistance $r$. The equivalent resistance between $A$ and $B$ is $R$. Now,if the keys $K_1$ and $K_2$ are closed,what will be the new equivalent resistance?

Two resistances of $400 \Omega$ and $800 \Omega$ are connected in series with a $6 \text{ V}$ battery of negligible internal resistance. $A$ voltmeter of resistance $10000 \Omega$ is used to measure the potential difference across the $400 \Omega$ resistor. The error in the measurement of potential difference in volts is approximately:

For the circuits $A$ and $B$ as shown in the figure,identify the correct option.

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:

$A$ resistance network is connected to a battery as shown in the figure below. If the internal resistance of the battery is $5 \ \Omega$,then the value of $R$ (in $\Omega$) for maximum power delivered to the network is

Calculate the voltage across $AB$ terminals in the given circuit.