What will happen when a $40\, W$,$220\, V$ lamp and a $100\, W$,$220\, V$ lamp are connected in series across a $40\, V$ supply?

For which value of resistance $R$ does the galvanometer show zero deflection in the electrical circuit shown below (in $Omega$)?

If $X, Y$ and $Z$ in the figure are identical lamps,which of the following changes to the brightness of the lamps occur when switch $S$ is closed?

An electrical circuit consists of ten $100 \,\Omega$ resistors. Out of these $10$ resistors,a group of $n_1$ resistors are connected in parallel and another group of $n_2$ resistors are separately connected in parallel. These two groups are then connected in series and this combination is connected to a voltage source of $100 \,V$. If the net current through the circuit is $2.5 \,A$,the values of $n_1$ and $n_2$ are:

An electric bulb rated for $500\, W$ at $100\, V$ is used in a circuit having a $200\, V$ supply. The resistance $R$ that must be put in series with the bulb,so that the bulb draws $500\, W$,is ................. $\Omega$.

The actual value of resistance $R$,shown in the figure is $30\,\Omega$. This is measured in an experiment as shown using the standard formula $R_{measured} = \frac{V}{I}$,where $V$ and $I$ are the readings of the voltmeter and ammeter,respectively. If the measured value of $R$ is $5\%$ less than the actual value,then the internal resistance of the voltmeter is ................. $\Omega$.