Three resistors of resistances $10 \Omega, 20 \Omega$ and $30 \Omega$ are connected as shown in the figure. If the points $A, B$ and $C$ are at potentials $10 \mathrm{~V}, 6 \mathrm{~V}$ and 5 V respectively, then the ratio of the magnitudes of the currents through $10 \Omega$ and $30 \Omega$ resistors is

When a potentiometer is connected between the points $A$ and $B$ as shown in the circuit, balance point is obtained at 64 cm . When it is connected between $A$ and $C$, the balance point is 8 cm . If the potentiometer is connected between $B$ and $C$ the balance point will be

In the given part of a circuit, the potential at point $B$ is zero. Then, the potentials at $A$ and $C$ respectively, are