A regular hexagon of side 10 cm has a charge 5 µC at each of its vertices. The potential at the center of the hexagon is:
1. \(2.7\times10^{6}\)  V
2. 0
3. \(3.7\times10^{6}\) V
4. \(2.0\times10^{6}\) V

Two charges 5×10^-8 C and -3x10^-8 C are located 16 cm apart from each other. At what point on the line joining the two charges is the electric potential zero? Take the potential at infinity to be zero.

1. 10 cm from the positive charge between the charges.
2. 40 cm from the positive charge between the charges.
3. 10 cm from the negative charge between the charges.
4. 40 cm from the negative charge between the charges.

A cube of side b has a charge q at each of its vertices. The potential due to this charge array at the center of the cube is:
1. \(\frac{4q}{\sqrt3\pi\varepsilon_0b}\)
2. \(\frac{8q}{\sqrt3\pi\varepsilon_0b}\)
3. \(\frac{2q}{\sqrt3\pi\varepsilon_0b}\)
4. \(0\)

Two tiny spheres carrying charges of \(1.5\) µC and \(2.5\) µC are located \(30\) cm apart. What is the potential at a point \(10\) cm from the midpoint in a plane normal to the line and passing through the mid-point?
1. \(1.5\times 10^{5}\) V
2. \(1.0\times 10^{5}\) V
3. \(2.4\times 10^{5}\) V
4. \(2.0\times 10^{5}\) V

Two charged conducting spheres of radii a and b are connected to each other by a wire. The ratio of electric fields at the surfaces of the two spheres is: