JEE Main 2024 Physics question
A solenoid of length 0.5 m has a radius of 1 cm and is made up of 'm' number of turns. It carries a current of 5A. If the magnitude of the magnetic field inside the solenoid is 6.28 × 10 T, then the value of m is:
Answer: 500
Solution
B = μ₀mI/ℓ ⇒ m = Bℓ/(μ₀I) = 6.28 × 10⁻³ × 0.5/(4π × 10⁻⁷ × 5) = 500.