A particle with mass m and charge -q is projected with speed v₀ into the region between two parallel plates as shown.The potential difference between the two plates is V and their separation is d.The change in kinetic energy of the particle as it traverses this region is:

Question

Quizplus · Accepted Answer

The potential difference between the plates creates an electric field between them. As the charged particle moves through this electric field, it experiences a force given by F = qE, where E is the electric field strength. This force does work on the particle, causing it to gain or lose kinetic energy. Since the particle has a negative charge, it will be accelerated towards the positively charged plate. Therefore, the electric force and the direction of motion are in the same direction, and the work done by the electric force will be positive. The work done by the electric force on the particle is given by W = qV, where V is the potential difference between the plates. The change in kinetic energy of the particle as it traverses this region is equal to the work done on it by the electric force, which is qV. Since the charge on the particle is -q, the change in its kinetic energy will be -qV. Hence, the best choice is C.

A Particle with Mass M and Charge -Q Is Projected