Question

A long solenoid has 200 turns per cm and carries a current I. The magnetic field at its centre is 6.28 × 10^–2 weber/m². Another long solenoid has 100 turns per cm and it carries a current I/3. The value of the magnetic field at its centre is

(a) 1.05 × 10^–4Wb/m² 

(b) 1.05 × 10^–2Wb/m²

(c) 1.05 × 10^–5Wb/m² 

(d) 1.05 × 10^–3Wb/m² 

Answer 1

Correct Option(b) 1.05 × 10^–2Wb/m²

Explanation:

Magnetic field due to a long solenoid is given by