MHT CET202519 Apr 2025Evening ShiftPhysicsElectrostaticsActual
A charged particle of mass ' m ' and charge ' q ' is at rest. It is accelerated in a uniform electric field of intensity ' E ' for time ' t '. The kinetic energy of the particles after time t is
Options
- AE q m 2 t
- BE^2 q^2 t^2 2 m
- C2 E ^2 t ^2 mq ^2
- DEqt m
Correct answer
B. E^2 q^2 t^2 2 m
Step-by-step solution
The electric force on a charged particle in a uniform electric field is F = qE . By Newton's second law, the resulting acceleration is a = F/m = qE/m . Since the particle starts from rest, its velocity after time t becomes v = at = (qE/m)t . The kinetic energy is then KE = 1 2 mv^2 = 1 2 m ( qE m t )^2 = q^2E^2t^2 2m . This expression corresponds to option B .