A constant current i is kept flowing through a solenoid. Which of the following quantities will increase if an iron rod is introduced into the solenoid along its axis?

Step-by-step solution

When an iron rod is introduced into the solenoid, the medium inside the solenoid changes from air to iron. Iron is a ferromagnetic material with a relative permeability _r > 1 . The magnetic field at the centre of the solenoid is given by B = _r ₀ n i . Since _r > 1 and the current i is constant, the magnetic field increases. The magnetic flux linked with the solenoid is = N B A . As B increases, the magnetic flux also increases. The self-inductance of the solenoid is given by L = i = _r ₀ n^2 A l . Since _r > 1 ,