NEET Physics — Electrostatic Potential and Capacitance

A spherical conductor of radius 8 cm has a charge of \( 4 \times 10^{-8} \, \text{C} \). What is the potential at its surface? (Take \( \frac{1}{4 \pi \varepsilon_0} = 9 \times 10^9 \, \text{Nm}^2 \text{C}^{-2} \)).

Four charges \( +q, -q, +q, -q \) are at the corners of a square of side \( 2 \, \text{m} \) in order. What is the potential at the center? (Take \( \frac{1}{4 \pi \varepsilon_0} = 9 \times 10^9 \, \text{Nm}^2 \text{C}^{-2} \), \( q = 1 \, \mu\text{C} \)).

In a system of two identical charged spheres brought close together, why does the potential at the midpoint differ from the sum of their individual potentials?

A \( 10 \, \mu\text{F} \) capacitor charged to \( 60 \, \text{V} \) is connected to an uncharged \( 30 \, \mu\text{F} \) capacitor. What is the energy lost?

A point charge \( Q = 2 \times 10^{-6} \, \text{C} \) is placed at the origin. What is the electrostatic potential at a point \( P \) located at \( (3, 4, 0) \, \text{m} \) from the origin? (Take \( \frac{1}{4 \pi \varepsilon_0} = 9 \times 10^9 \, \text{Nm}^2 \text{C}^{-2} \)).