Question
Question: A long straight wire in the horizontal plane carries a current of 75 A in north to south direction, ...
A long straight wire in the horizontal plane carries a current of 75 A in north to south direction, magnitude and direction of field B at a point 3 m east of the wire is
A
4 × 10-6 T, vertical up
B
5 × 10-6 T, vertical down
C
5 × 10-6 T, vertical up
D
4 × 10-6 T, vertical down
Answer
5 × 10-6 T, vertical up
Explanation
Solution
From Ampere circuital law
The direction of field at the given point will be vertical up determined by the screw rule or right hand rule.