Question

A positively charged alpha particle projected towards west is deflected towards north by a magnetic field . Find out the direction of the magnetic field . Also state the rule which is used to find the direction of magnetic field in such case

Answer 1

Solution:

Since the positively charged particle is projected towards west, so the direction of current is towards west. Now the deflection is towards north, so the force is towards north.
According to Fleming's Left Hand Rule, if centre finger points in the direction of current (west), thumb points in the direction of force (north), then forefinger points in the direction of magnetic field (upwards). Thus, the magnetic field is in upward direction.

(Answer)