Fields (gravitational, electric, magnetic)
⏱ ~3-min readAceMark Guide
What this topic is really about
Gravitational potential is defined as zero at infinity because it is the point furthest from the mass where the gravitational field has no influence. As you move closer to a mass, work is done by the field, making the potential negative. Option A is incorrect because potential does not increase to infinity, and Option C describes the potential at any finite distance from the mass, not at infinity itself.
According to Faraday's law of electromagnetic induction, the induced electromotive force (EMF) is directly proportional to the rate of change of magnetic flux linkage. Option A is incorrect because a constant, strong magnetic field with no change will not induce any EMF. Option C is wrong because coil resistance affects the induced current, not the EMF itself.
See the mechanism
Gravitational potential is defined as zero at infinity because it is the point furthest from the mass where the gravitational field has no influence. A diagram for this topic isn't available yet — the worked example below walks the same reasoning step by step.
An exam-style question, fully explained
Gravitational potential at infinity is defined as:
- Identify what the question tests: Gravitational potential at infinity is defined as:.
- Gravitational potential is defined as zero at infinity because it is the point furthest from the mass where the gravitational field has no influence.
- As you move closer to a mass, work is done by the field, making the potential negative.
- Option A is incorrect because potential does not increase to infinity, and Option C describes the potential at any finite distance from the mass, not at infinity itself.
Traps the examiner sets
- Option A is incorrect because potential does not increase to infinity, and Option C describes the potential at any finite distance from the mass, not at infinity itself.
- Option A is incorrect because a constant, strong magnetic field with no change will not induce any EMF.
Test your recall
Answer each from memory — you'll see instantly whether you're right and why.
Run a focused 10-question mini-mock on Fields (gravitational, electric, magnetic) and see it stick.
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