Q. 21
First a set of n equal resistors of R each is connected in series to a battery of emf E and internal resistance R. 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 becomes 10 times. What is ‘n’?
Answer :
When n resistors are in series and internal resistor is also R, then current value is,
.
When resistors are in parallel, the current becomes,
.
According to the question, I’=10I.
So,
.
Thus, n =10.
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