Three similar cells, each of e.m.f. $2 V$ and internal resistance sends the same current through an external resistance of $2$$\mathrm{\Omega }$, when connected in series or parallel. The strength of the current flowing through the external resistance is

Two cells of emf $10 \mathrm{V}$ and $15 \mathrm{V}$ are connected in parallel to each other between points $A$and $B$. The cell of emf $10 \mathrm{V}$ is ideal but the cell of emf $15 \mathrm{V}$ has an internal resistance $1 \mathrm{\Omega }$. The equivalent emf between $A$and $B$ is

Two batteries, one of emf $18 \mathrm{V}$ and internal resistance $2 \mathrm{\Omega }$ and the other of emf $12 \mathrm{V}$ and internal resistance $1 \mathrm{\Omega }$ are connected, as shown in the figure. Voltmeter $V$ will record a reading of

The figure shows a network of currents. Study the diagram and find the magnitude of current $I$.

The current in the branch $CD$, in the circuit shown below, will be

See the electrical circuit shown in the figure. Which of the following equations is a correct equation for it?