Q.

10 resistors, each of resistance R are connected in series to a battery of emf E and negligible internal resistance. Then those are connected in parallel to the same battery, the current is increased n times. The value of n is                    [2023]

1 1  
2 1000  
3 10  
4 100  

Ans.

(4)

Net resistance in series combination,

RN=R1+R2++R10

=10+10++10=10×10=100Ω                      ...(i)

Same number of resistors and each of same magnitude connected in parallel combination,

      R'N=(1R1+1R2++1R10)-1

            =(1+1++110)-1=1010=1Ω                               ...(ii)

Using (i) and (ii), I'I=V.RNR'N.V=1001

Thus, option (4) is correct.