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The magnetic flux through a circuit of resistance R changes by an amount Δφ in a time Δ t. Then the total quantity of electric charge Q that passes any point in the circuit during the time Δ t is represented by

Asked in NEET 2004 · Induced charge

Answer: (2) Q=(Δφ)/R

Step-by-step solution

The induced current is i=ε/R=1/R(dφ)/(dt).

Integrating over the interval,

Q=∫ i dt=1/R∫ dφ=(Δφ)/R.

The Δ t cancels: the charge depends only on how much the flux changed, not on how quickly.

A slow change gives a small current for a long time and a fast change a large current briefly,

and both move the same charge.

Why the other options are wrong

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