$A$ battery of $6 \text{ V}$ is connected to the ends of a uniform wire $3 \text{ m}$ long and of resistance $100 \Omega$. The potential difference between two points $50 \text{ cm}$ apart on the wire is: (in $\text{ V}$)

When a constant voltage is applied across the ends of a metallic wire,the heat produced in the wire will be doubled if:

In the circuit shown below,if the potential at point $A$ is taken to be zero,the potential at point $B$ is .............. $V$.

The equivalent resistance between the points $A$ and $B$ is (in $\Omega$):

When a potential difference $V$ is applied across a wire of resistance $R$,it dissipates energy at a rate $W$. If the wire is cut into two halves and these halves are connected in parallel across the same supply,the energy dissipation rate will become:

Two cells of $e.m.f.$ $E_1$ and $E_2$ and of negligible internal resistances are connected with two variable resistors as shown in the figure. When the galvanometer shows no deflection,the values of the resistances are $P$ and $Q$. What is the value of the ratio $E_2/E_1$?