By a cell,a current of $0.9\, A$ flows through a $2\, \Omega$ resistor and $0.3\, A$ flows through a $7\, \Omega$ resistor. The internal resistance of the cell is ............ $\Omega$.

$A$ student was trying to construct the circuit shown in the figure below marked $(a)$,but ended up constructing the circuit marked $(b)$. Realising her mistake,she corrected the circuit,but to her surprise,the output voltage (across $R$) did not change. The value of resistance $R$ is ............ $\Omega$

An ideal cell of emf $10\, V$ is connected in the circuit shown in the figure. Each resistance is $2\, \Omega$. The potential difference (in $V$) across the capacitor when it is fully charged is

$A$ battery of $e.m.f.$ $10 \, V$ and internal resistance $3 \, \Omega$ is connected to a resistor $R$ as shown in the figure. If the current in the circuit is $0.5 \, A$,then the resistance of the resistor $R$ will be ............. $\Omega$.

The series combination of two batteries,both of the same emf $10 \; V,$ but different internal resistances of $20 \; \Omega$ and $5 \; \Omega,$ is connected to the parallel combination of two resistors $30 \; \Omega$ and $R \; \Omega.$ If the voltage difference across the battery of internal resistance $20 \; \Omega$ is zero,the value of $R$ (in $\Omega$) is:

In the given circuit, the current flowing through the resistance $20 \, \Omega$ is $0.3 \, A$, while the ammeter reads $0.8 \, A$. What is the value of $R_1$ in $\Omega$?