What is the potential energy of two equal positive point charges of \(1~ \mu \text{C}\) each held \(1\) m apart in the air?
1. | \(9 \times 10^{-3}~\text{J}\) | 2. | \(9 \times 10^{-3}~\text{eV}\) |
3. | \(2~\text{eV/m}\) | 4. | zero |
Three charges \(Q\), \(+q \) and \(+q \) are placed at the vertices of an equilateral triangle of side \(l\) as shown in the figure. If the net electrostatic energy of the system is zero, then \(Q\) is equal to:
1. | \(-\frac{q}{2} \) | 2. | \(-q\) |
3. | \(+q\) | 4. | \(\text{zero}\) |
Two charges q1 and q2 are placed 30 cm apart, as shown in the figure. A third charge q3 is moved along the arc of a circle of radius 40 cm from C to D. The change in the potential energy of the system is , where k is:
1. | 8q2 | 2. | 8q1 |
3 | 6q2 | 4. | 6q1 |