The Core of a Long Solenoid with 1000 Turns/m and a Current

The core of a long solenoid with 1000 turns/m and a current of 0. 5 A is filled with an unknown material. It is found that the magnetic field along the axis of the solenoid increases by 0.0017%. What is the magnetic susceptibility of the unknown material?

A) 1.7 × 10^-5
B) 3.4 × 10^-5
C) 0.0048
D) -3.4 × 10^-5
E) 0.0021