MHT CET202613 April 2026Evening ShiftPhysicsMagnetic Effects of CurrentActual
Two long straight wires are arranged parallel to each other and are kept 20 cm apart in vacuum. They carry currents of 2 A and 4 A respectively in the same direction. What will be the magnetic force on a length of 10 cm of either wire? ( ₀ = 4 10⁻⁷ SI units)
Options
- A10⁻⁷ N
- B2 10⁻⁷ N
- C4 10⁻⁷ N
- D8 10⁻⁷ N
Correct answer
D. 8 10⁻⁷ N
Step-by-step solution
The magnetic force on a length L of either wire is given by the formula: F = ₀ I₁ I₂ L 2 d Given: I₁ = 2 A I₂ = 4 A d = 20 cm = 0.2 m L = 10 cm = 0.1 m ₀ = 4 10⁻⁷ T m/A Substituting the values: F = 4 10⁻⁷ 2 4 0.1 2 0.2 F = 2 10⁻⁷ 0.8 0.2 F = 8 10⁻⁷ N Answer: 8 10⁻⁷ N