First a set of n equal resistors of R each are 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 is increased 10 times. What is 'n'?

Explanation

In series combination of resistors, current I is given by `I=(E)/(R+nR')`
whereas in parallel combination current 10 I is given by
`(E)/(R+(R)/(n))=10I`
Now, according to problem,
`(1+n)/(1+(1)/(n))implies10=((1+n)/(n+1))nimpliesn=10`