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Question
Two long parallel wires kept 2 m apart carry 3A current each, in the same direction. The force per unit length on one wire due to the other is ______.
Options
4.5 × 10-5 Nm-1, attractive
4.5 × 10-7 N/m, repulsive
9 × 10-7 N/m, attractive
9 × 10-5 N/m, attractive
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Solution
Two long parallel wires kept 2 m apart carry 3A current each, in the same direction. The force per unit length on one wire due to the other is 9 × 10-7 N/m, attractive.
Explanation:
Given I1 = I2 = 3 A, d = 2 m, the current is flowing in the same direction,
Now, `F/l = (mu_0I_1I_2)/(2pid)`
= `(4pi xx 10^-7 xx 3 xx 3)/(2pi xx 2)`
= 9 × 10-7 N/m
`F/l = 9 xx 10^-7` N/m
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