A positive charge Q is uniformly distributed along a circular ring of radius R. A small test charge q is placed at the centre of the ring as shown in figure. Then
, and is displaced away from the centre in the plane of the ring, it will be pushed back towards the center.
and is displaced away from the centre in the plane of the ring, it will never return to the centre and will continue moving till it hits the ring.
it will perform SHM for small displacement along the axis.
Text Solution
Verified by ExpertsD
At the center of the ring, 
when a positive charge 
is displaced away from the centre in the plane of the ring, say to the right, force of repulsion on q, due to charge on right half increases and due to charge on left half decreases. Therefore, charge q is pushed back towards the centre. So option a. is correct.
When charge q is negative ( 
), force is of attraction, Therefore, charge q displaced to the right continues moving to the right till it hits the ring.
Along the axis of the ring, at a distance 
from the center,
If charge q is negative ( 
), it will perform SHM for small displacement along the axis.
Prepare Smarter with CGP Edu
Get practice questions, solutions, and test series in one place.
Write a Review
Share your experience with this question and solution.
Commentary
Send your comment, doubt, correction, or feedback to admin.
Similar Questions
Explore conceptually related problems