$A$ voltmeter of resistance $150 \Omega$ connected across a cell of e.m.f. $3 \ V$ reads $2.5 \ V$. What is the internal resistance of the cell (in $\Omega$)?

Find the current passing through the battery immediately after the key $(K)$ is closed. It is given that initially all the capacitors are uncharged. (Given that $E = 5 \, V$, $R = 6 \, \Omega$) (in $A$)

An electric bulb rated as $200 \, W$ at $100 \, V$ is used in a circuit having $200 \, V$ supply. The resistance $R$ that must be put in series with the bulb so that the bulb delivers the same power is $..... \, \Omega$.

The current flowing in the given circuit is $0.1\,A$. The potential difference between the points $X$ and $Y$ is ................ $V$.

The resistance of the filament of an electric bulb changes with temperature. If an electric bulb rated $220\,V$ and $100\,W$ is connected to a $(220 \times 0.8)\,V$ source,then the actual power consumed would be:

$A$ current of $2\,A$ flows in a system of conductors as shown. The potential difference $(V_A - V_B)$ will be ............ $V$.