Current Electricity and Electrical InstrumentHard

Question

A set of 'n' equal resistors, of value 'R' each, are connected in series to a battery of emf 'E' and internal resistance 'R'. The current drawn is I. Now, the 'n' resistors are connected in parallel to the same battery. Then the current drawn from battery comes 10 I. The value of 'n' is :-

Options

A.

10

B.

11

C.

20

D.

9

Solution

I=EnR+R               .........(1)101=ERn+R=nER+nR   ........(2)
From (1) & (2),
nER+nR=10EnR+R
n = 10

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