JEE Main20204 Sep 2020Evening ShiftPhysicsMotion in One DimensionActual
A particle of charge q and mass m is subjected to an electric field E = E 0 1 – a x 2 in the x - direction, where a and E 0 are constants. Initially the particle was at rest at x = 0 . Other than the initial position the kinetic energy of the particle becomes zero when the distance of the particle from the origin is :
Options
- Aa
- B2 a
- C3 a
- D1 a
Correct answer
C. 3 a
Step-by-step solution
W ex = ΔK              K 1 - K 1 = 0 ∫ 0 x qEdx = 0  q  ∫ 0 x E 0 1 - Qx 2 dx = 0 qE 0 ∫ 0 x 1 - ax 2 dx = 0 x - ax 3 3 = 0 1 - ax 2 3 = 0 ax 2 3 = 1 x 2 = 3 a x = 3 a