Two parallel wires in free spaces are `10cm` apart and each carries a current of `10A` in the same direction. The force one wire exerts on the other per metre of length is

Options

A. `2 xx 10^(-4)N`, repulsive
B. `2 xx10^(-7)N`, repulsive
C. `2 xx 10^(-4)N`, attractive
D. `2 xx 10^(-7)N`, attractive

Answer

C

Explanation

Distance between two parallel wires (x) = 10cm = 0.1m, current in each wire `=I_(1) = I_(2) = 10A` and length of wire (l)= 1m.
`:.` Force on the wire `(F) = (mu_(0)I_(1). I_(2) xx l)/(2pi x)`
`=((4 pi xx 10^(-7)) xx 10 xx 10 xx 1)/(2pi xx 0.1) = 2 xx 10^(-4)N`
Since the current is flowing in the same direction, therefore the force will be attractive.