Question

A coil having 100 closely wound turns and area of cross-section 300 mm² carries a current of 5 mA. The magnitude of the magnetic moment associated with the coil is ______.

Options

• 6 × 10⁻⁴ Am²

• 3 × 10⁻⁵ Am²

• 1.5 × 10⁻⁴ Am²

• 5 × 10⁻⁵ Am²

Answer 1

A coil having 100 closely wound turns and area of cross-section 300 mm² carries a current of 5 mA. The magnitude of the magnetic moment associated with the coil is 1.5 × 10⁻⁴ Am².

Explanation:

Given: Number of turns (N) = 100

Current (I) = 5 mA = 5 × 10⁻³ A

Area (A) = 300 mm² = 300 × 10⁻⁶ m²

The magnetic moment of a current-carrying coil is a vector quantity that represents the magnetic strength and orientation of the coil.

Magnetic moment M = NIA

= 100 × (5 × 10⁻³) × (300 × 10⁻⁶)

= 100 × 5 × 300 × 10⁻⁹

= 150000 × 10⁻⁹

= 1.5 × 10⁵ × 10⁻⁹

= 1.5 × 10⁻⁴ Am²

∴ The magnetic moment is 1.5 × 10⁻⁴ Am².