In an oscillating $LC$ circuit the maximum charge on the capacitor is $Q$. The charge on the capacitor when the energy is stored equally between the electric and magnetic fields is

Potential in the $x-y$ plane is given as $V = 5(x^2 + xy)\, volts$. The electric field at the point $(1, -2)$ will be

A series combination of $n_1$ capacitors, each of value $C_1$, is charged by a source of potential difference $4V$. When another parallel combination of $n_2$ capacitors, each of value $C_2$, is charged by a source of potential difference $V$ , it has the same (total) energy stored in it, as the first combination has. The value of $C_2$ , in terms of $C_1$, is then

If potential at centre of uniformaly charged ring is $V_0$ then electric field at its centre will be (assume radius $=R$)

In the circuit shown in the figure, the potential difference across the $4.5\,\,\mu F$ capacitor is.......$volts$

Electric field at a point varies as $r^o$ for