Question

An electron moving with a speed of 8.4 105 m/s in the positive z direction experiences zero magnetic force. When it moves in the positive x direction it experiences a force of 2.1 10-13 N that points in the negative y direction. What is the magnitude and direction of the magnetic field?
magnitude __________ T

Answer 1

Answer:

magnitude of the magnetic field must be 1.56 T

Explanation:

As we know that the magnetic force on moving charge is given as

$F = q(\vec v \times \vec B)$

now when charge is moving along z direction then magnetic force is ZERO

so here we can say that magnetic field must be parallel to velocity of the charge i.e. along z direction

now when charge is moving along x direction then we have

$F = qvB$

$2.1 \times 10^{-13} = (1.6 \times 10^{-19})(8.4 \times 10^5) B$

so we have

$B = 1.56 T$

magnitude of the magnetic field must be 1.56 T