A straight wire of resistance $R$ is bent in the shape of $f_d$ square. A cell of emf 12 V is connected between two adjacent corners of the square. The potential difference across any diagonal of the square is

In the given circuit, if the potential at point $B$ is 24 V , the potential at point $A$ is

A block has dimensions $1 \mathrm{~cm}, 2 \mathrm{~cm}$ and 3 cm . Ratio of the maximum resistance to minimum resistance between any palr of opposite faces of the block is

A current of 6 A enters one corner $P$ of an equilateral triangle $P Q R$ having three wires of resistance $2 \Omega$ each and leaves by the corner $R$ as shown in figure. Then the currents $I_1$ and $I_2$ are respectively