Magnetic Effects Of Current Question 303

Question: An electron is moving along positive x-axis. To get it moving on an anticlockwise circular path in x-y plane, a magnetic filed is applied [MP PMT 1999]

Options:

A) Along positive y-axis

B) Along positive z-axis

C) Along negative y-axis

D) Along negative z-axis

Show Answer

Answer:

Correct Answer: B

Solution:

To move the electron in xy plane, force on it must be acting in the y-direction initially. The direction of $ \vec{F} $ is known, and the direction of v is known, hence by applying Fleming’s left hand rule, the direction of magnetic field is also determined.