The internal resistance of a cell of emf $4 \text{ V}$ is $0.1 \ \Omega$. It is connected to an external resistance of $3.9 \ \Omega$. The terminal voltage across the cell will be . . . . . . . (in $\text{ V}$)

In the given diagram,an ideal voltmeter $V$ reads $1.45\,V$. Then the relation between $r_1$ and $r_2$ is:

$n$ identical cells each of $e.m.f.$ $E$ and internal resistance $r$ are connected in series. An external resistance $R$ is connected in series to this combination. The current through $R$ is

For an open circuit condition,what is the value of the terminal voltage of a cell?

An electric eel generates an electric current using biological cells called electroplaques. The eel has a total of $5000$ electroplaques arranged in $100$ rows. This arrangement is shown in the figure. Each electroplaque has an $emf$ of $0.15\ V$ and an internal resistance of $0.25\ \Omega$. The water surrounding the eel completes the circuit between its head and tail. If the resistance of the water is $500\ \Omega$,the electric current generated by the eel in the water is .......... $A$.

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