The equivalent resistance between the points $A$ and $B$ is (in $\Omega$):

The figure shows a network of resistors and a battery. If $1\,A$ current flows through the branch $CF$,then answer the following questions. The current through:

In the circuit shown,the cells $A$ and $B$ have negligible internal resistances. For $V_A = 16 \ V$,$R_1 = 600 \ \Omega$,and $R = 200 \ \Omega$,the galvanometer shows no deflection. The value of $V_B$ is $...V$.

What is the current $I$ shown in the given circuit?

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 $\delta R_P \approx \delta R_Q$?

In the circuit shown,the reading of the Ammeter is doubled after the switch is closed. Each resistor has a resistance $R = 1\,\Omega$ and the ideal cell has an $e.m.f. = 10\, V$. Then,the Ammeter has a coil resistance equal to ................ $\Omega$.