In the given circuit,when the switch $S$ is closed,what is the current in amperes flowing through it?

Three resistances $A, B$ and $C$ having values $3R, 6R$ and $R$ respectively form a network as shown. When a potential difference is applied across the network,the thermal powers dissipated by $A, B$ and $C$ are in the ratio:

If each resistance in the figure is $9 \Omega$,then the reading of the ammeter $(A)$ is (in $A$)

Consider the two circuits $P$ and $Q$ shown below,which are used to measure the unknown resistance $R$. In each case,the resistance is estimated by using Ohm's law $R_{\text{est}} = \frac{V}{I}$,where $V$ and $I$ are the readings of the voltmeter and the ammeter,respectively. The meter resistances $R_V$ and $R_A$ are such that $R_A \ll R \ll R_V$. The internal resistance of the battery may be ignored. The absolute error in the estimate of the resistance is denoted by $\delta R = |R - R_{\text{est}}|$.
$(a)$ Express $\delta R_P$ in terms of the given resistance values.
$(b)$ Express $\delta R_Q$ in terms of the given resistance values.
$(c)$ For what value of $R$ will $\delta R_P \approx \delta R_Q$?

To verify Ohm's law,a student connects the voltmeter across the battery as shown in the figure. The measured voltage is plotted as a function of the current,and the following graph is obtained. If $V_0$ is almost zero,identify the correct statement.

The battery in the diagram is to be charged by the generator $G$. The generator has a terminal voltage of $120 \ V$ when the charging current is $10 \ A$. The battery has an $emf$ of $100 \ V$ and an internal resistance of $1 \ \Omega$. In order to charge the battery at $10 \ A$ charging current,the resistance $R$ should be set at ................ $\Omega$.