(A) The graph between magnetic susceptibility and magnetising field is as shown in (III).
(B) For \( x < a \), the magnetic field due to a current-carrying wire is given by: \[ B = \frac{\mu_0 I x}{2 \pi a^2}, \] matching graph (IV).
(C) For \( x > a \), the magnetic field due to a current-carrying wire is given by: \[ B = \frac{\mu_0 I}{2 \pi x}, \] matching graph (I).
(D) The magnetic field inside a solenoid varies with distance as shown in (II).
A body of mass 1000 kg is moving horizontally with a velocity of 6 m/s. If 200 kg extra mass is added, the final velocity (in m/s) is: