Question

A 20 cm-long solenoid is constructed of 2900 turns of wire wrapped around a 2 cm diameter core in the direction shown in the figure. A pickup coil composed of 170 turns of wire is wrapped tightly around the core at the middle of the solenoid in the opposite direction. The resistance of the pickup coil is 3Ω. The current through the solenoid is initially 0 and then increases to 20 A in 2 seconds.

(Questions and image below.)

Answer 1

a) When the current is 20 A (see figure for the direction) what is the magnitude of the magnetic field in the solenoid? Express your answer using three significant figures. Answer in T.

b) When the current is 20 A (see figure for the direction) what is the direction of the magnetic field in the solenoid?

c) When the current is 12 A in the solenoid, what is the magnetic flux, ΦB, through one turn of the pickup coil? Answer in Tm^2.

Note: Use the maximum current given in the initial description and Part A - not the current in Part C.

d) During the 2 seconds when the current in the solenoid is increasing what is the EMF (Volts) induced in the 170 turn pickup coil? Answer in V.

e) What is the direction of the induced current through the resistor?

f) What is the magnitude of the induced current through the resistor? Answer in A.

Answer 2

I'd appreciate if someone can help me as quickly as possible. This is due online soon, and I'm really lost and need every point I can get.

Answer 3

I know b) is UP and e) is RIGHT but I need help with a, c, d, and f still!