Question

What should be the current in a circular coil of radius 5 cm to annule Bₕ = 5 × 10⁻⁵ T?

A. 0.4A
B. 4A
C. 40A
D. 1A

Answer 1

To annul a magnetic field strength of Bₕ = 5 × 10⁻⁵ T in a circular coil of radius 5 cm, the current in the coil should be approximately 40 A.

Step-by-step explanation:

To annul a magnetic field strength of Bₕ = 5 × 10⁻⁵ T in a circular coil of radius 5 cm, the current in the coil can be calculated using the equation Bₕ = μ₀ × I × N / A, where μ₀ is the permeability of free space, I is the current, N is the number of turns, and A is the area of the coil.

Plugging in the given values, we have:

5 × 10⁻⁵ = (4π × 10⁻⁷) × I × 1 / (π × (0.05)²)

Simplifying the equation, the current should be approximately 40 A, so the correct answer is C. 40A.