A wire of length L and 3 identical cells is now connected in series with a wire of the same material and cross-section but of length by the same amount `Delta T` in the same time t. the value of N is:-
A. 4
B. 6
C. 8
D. 9
Correct Answer - A
`L=(mu_(0)N^(2)pir^(2))/l`
length of wire =`N 2pir`=Constant(=`C`suppose)
`therefore L=mu_(0)(C/(2pir))^(2) (pi r^(2))/l therefore L prop 1/l`
`therefore` Self inductance will become `2L`.