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NEET PHYSICSELECTRIC CHARGES AND FIELDSMedium

Question

Two equal positive charges QQ are fixed at points (a,0)(a, 0) and (a,0)(-a, 0) on the x-axis. An opposite charge q-q at rest is released from a point (0,y)(0, y) on the y-axis. The charge q-q will:

A

move to infinity.

B

move to the origin and rest there.

C

undergo SHM about the origin.

D

execute oscillatory periodic motion but not SHM.

Step-by-Step Solution

The charge q-q experiences attractive forces from both positive charges +Q+Q. The horizontal components of these forces cancel out, while the vertical components add up to provide a net restoring force directed towards the origin. The magnitude of this force is Fnet=2kQqy(a2+y2)3/2F_{net} = \frac{2kQqy}{(a^2 + y^2)^{3/2}}. For Simple Harmonic Motion (SHM), the restoring force must be directly proportional to the displacement (FyF \propto -y). Here, the force is proportional to yy only if yay \ll a (small oscillations). For general release points, the force is non-linear with respect to distance. Therefore, the charge executes oscillatory periodic motion, but it is not SHM. (See NCERT Physics Class 12, Chapter 1).

Exam Context & Concepts Covered

This question aligns with the NEET PHYSICS syllabus, specifically targeting concepts from ELECTRIC CHARGES AND FIELDS. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

PHYSICSELECTRIC CHARGES AND FIELDSpositivechargespointsoppositecharge

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