A circular loop of wire of radius r = 50 cm and resistance R = 15 Ohms sits inside of a solenoid such that the axis of symmetry of the solenoid intersects the center of the loop. The solenoid has 800 turns and a

length of 40 cm. We measure an induced current in the loop of wire of I = 2.5 A for a period of 18 ms.

What is the change in current in the solenoid which could have caused the induced current in the wire loop?