In the following circuit diagram,$E = 4\,V, r = 1\,\Omega$ and $R = 45\, \Omega$,then the reading of the ammeter $A$ will be

In the given electrical circuit,the potential difference between points $P$ and $Q$ is ........... $V$.

$R_1$ and $R_2$ are two resistors made of different materials. The temperature coefficient of resistance for $R_1$ is $\alpha$ and for $R_2$ is $-\beta$. If the resistance of the series combination of $R_1$ and $R_2$ does not change with temperature,then the ratio of the resistances of the two wires is:

The potential difference between points $A$ and $B$ of the adjoining figure is

In the circuit shown, the heat produced in $5 \Omega$ resistance due to current $I_2$ is $50 \text{ J/s}$. Then, the heat generated per second in $2 \Omega$ resistance is (in $\text{ J/s}$)

In the figure shown,the capacity of the capacitor $C$ is $2\,\mu F$. The current in the $2\,\Omega$ resistor is ............... $A$.