Two identical cells each of emf $1.5\,V$ are connected in series across a $10\,\Omega$ resistance. An ideal voltmeter connected across $10\,\Omega$ resistance reads $1.5\,V$. The internal resistance of each cell is $......\Omega$.

Each cell has emf $1.5 \ V$ and internal resistance $1 \ \Omega$. The minimum number of such cells required to produce a maximum current of $1.5 \ A$ in an external load resistance of $30 \ \Omega$ is

When two identical batteries of internal resistance $1 \Omega$ each are connected in series across a resistor $R$,the rate of heat produced in $R$ is $P_1$. When the same batteries are connected in parallel across $R$,the rate of heat produced is $P_2$. If $P_1 = 2.25 P_2$,then the value of $R$ is (in $Omega$)

Consider a parallel combination of the cells shown in the figure. The potential difference between $B_1$ and $B_2$ is

It is easier to start a car engine on a hot day than on a cold day. This is because the internal resistance of the car battery

$A$ $10\,V$ battery with internal resistance $1\,\Omega$ and a $15\,V$ battery with internal resistance $0.6\,\Omega$ are connected in parallel to a voltmeter (see figure). The reading in the voltmeter will be close to ................ $V$.