Question

The earth's magnetic field at a certain point is 0.70 gauss. This field is to be annulled by the magnetic field at the centre of a circular conducting loop 5 cm in radius. The requires current is about

Answer 1

Answer:

Explanation:

=> It's given here,

The earth's magnetic field = 0.77 gauss = 0.00007Wb/m^2

Radius of circular conducting loop = 5 cm = 5 * 10^-2 m

Current i = ?

=> Magnetic field at the centre of circular loop:

=> B = μ$_{0}$ / 4π * 2πi / r

=> 0.00007 =  μo*n*i / 2r

=>  0.00007 =  μo*n*i / 2r

=>  0.00007 = 4π * 10^-7* i / 2* 5 * 10^-2      [μo = 4π * 10^-7 ]

=> 0.00007 = 10^-7 * 2 * 3.14 * i /  5 * 10^-2  

=> i = 0.00007 * 5 * 10^-2 / 10^-7 * 2 * 3.14

=> i = 7 * 10^-5 * 5 * 10^-2 / 10^-7 * 2 * 3.14

=> i = 35 *10^-7 /  10^-7 * 6.28

=> i ≈ 5.57 A

Thus, The requires current is about 5.57 A.