Question

Two identical positive charges are fixed on x-axis at +a and -a. A charge particle of mass m is released from rest under gravity from some height along y-axis. The particle just reaches origin, then choose correct options.

• A. Particle has negative charge
• B. Total potential energy continuously increases.
• C. Total potential energy first increases, then decreases
• D. Total potential energy first decreases, then increases

Answer 1

The correct option is D Total potential energy first decreases, then increases

The particle just managed to reach the ground, which means the charges are repelling the mass. So, the mass is positively charged.
The kinetic energy of the system is zero initially and finally, but it is maximum in between. This means, the potential energy is maximum initially and finally and is minimum in between.