A particle of charge +q and mass m moving under the influence of a uniform electric field $E \hat{i}$ and uniform magnetic field $B \hat{k}$ follows a trajectory from P to Q as shown in figure. The velocities at P and Q are vi and $2 v (- \hat{j})$ , Which of the following statement(s) is/are correct?

Question

diagram

TestHub · Accepted Answer

Work-energy from P to Q (B does no work): $qE (2 a) = \frac{1}{2} m (4 v^{2} - v^{2}) \Rightarrow E = \frac{3 m v ^{2}}{4 q a}$ - (A) correct.

Rate of work by E at P: $qE v = \frac{3 m v ^{3}}{4 a}$ - (B) correct, (C) wrong.

At Q the velocity is along $- \hat{j}$ , perpendicular to E, and B never does work - (D) correct.

Physics - Magnetism Question with Solution | TestHub

Options:(select one or more)

Doubts & Discussion