Question

A current of one ampere is passed through a
straight wire of length 2 metre. The magnetic
field at a point in air at a distance of 3 m from
one end of the wire but lying on the axis of the
wire will be
1) u./21 2) un / 41 3) Mo/81 4) Zero
otor corries current​

Answer 1

Answer:

The correct option (d) zero

For straight wire,

B = (μ0/4π)(I/d)(sinθ1 + sinθ2)

here

θ1 = θ2 = 0, as sinθ = sin0 = 0

Hence B = 0