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First, a set of n equal resistor of 10 Ω each are connected in series to a battery of emf 20 V and internal resistance 10 Ω. A current I is observed to flow. Then, the n resistors are connected in parallel to the same battery. It is observed that the current is increased 20 times, then the value of n is ______.

Asked in JEE Main 27th Aug 1st Shift 2021 · Terminal voltage and internal resistance

Answer: 20

Step-by-step solution

Series: I=(20)/(10n+10).

Parallel: I'=(20)/(10/n+10).

(I')/I=(10(n+1))/(10(1+n)/n)=n.

n=20.

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