Two concentric current loops lie in the same plane. The smaller loop has a radius of 2.7cm and a current of 12 A. The bigger loop has a current of 20 A. The magnetic field at the center of the loops is found to be zero. What is the radius of the bigger loop?

Explanation:

The B-field at the center of a circular loop of radius, r and current, I is;

Magnetic field, B = (μ × I) ÷ 2pi × R

Given:

rs = 2.7 cm

= 0.027 m

Is = 12 A

Ib = 20 A

(μ × Is)/2 × rs = (μ × Ib)/2 × rb

Inputting values,

rb = (20 × 2 × 0.027)/12 × 2

= 0.045 m

= 4.5 cm.

mass X velocity

Explanation:

The momentum of a body is the product of its mass and velocity