Question

At very close point of the axis of a current carrying circular coil of radius r the value of magnetic field decreases by a fraction of 5% with respect to centre value .

Answer 1

Answer:

Magnetic field increases by 5%

Explanation:

 we know that,

       B=μ₀ i / 2r

     R = r - 0.05r

         R = 0.95 r

     B¹ = μ₀ i / 2R = μ₀ i / 2(0.95) r

 B¹ = μ₀ i / 1.9 r

    B¹  / B =  1.05

 ΔB  % = (B¹  - B ) / B  x 100

            = (1.05 - 1) X 100

                = 0.05 X 100

               =  5 %