MHT CET202620 April 2026Morning ShiftPhysicsMagnetic Effects of CurrentActual
A long solenoid carrying a current produces a magnetic field ' B ' along its axis. If the currunt is tripled and the number of turns per cm is halved then new value of magnetic field will be
Options
- AB 2
- BB
- C3 2 B
- D3B
Correct answer
C. 3 2 B
Step-by-step solution
The magnetic field produced by a long solenoid along its axis is given by B = ₀ n I , where n is the number of turns per unit length and I is the current. Given that the new current is I' = 3I and the new number of turns per unit length is n' = n 2 . The new magnetic field B' is: B' = ₀ n' I' B' = ₀ ( n 2 ) (3I) B' = 3 2 ₀ n I B' = 3 2 B Answer: 3 2 B