AIIMS2005PhysicsElectrostatics
Four point +ve charges of same magnitude (Q) are placed at four corners of a rigid square frame as shown in figure. The plane of the frame is perpendicular to Z -axis. If a -ve point charge is placed at a distance z away from the above frame (z< < ) then
Options
- A-ve charge oscillates along the Z -axis
- Bit moves away from the frame
- Cit moves slowly towards the frame and stays in the plane of the frame
- Dit passes through the frame only once.
Correct answer
A. -ve charge oscillates along the Z -axis
Step-by-step solution
The negative charge oscillates, the resultant force acts as a restoring force and is component, proportional to displacement. When it reaches the plane X Y , the resultant force is zero and the mass moves down due to inertia. Thus oscillation is set. [This problem is similar to