Concept #1: Faraday's Law
Practice: Two solenoids are placed end to end, with one solenoid connected to a variable power source, and the other solenoid connected to a 10 Ω resistor. The first solenoid has 10 turns per cm and has as an initial current of 2 A, and the second solenoid has 5 turns and a radius of 2 cm.
a) What is the change in magnetic field emitted by the first solenoid if the current increases from 2 A to 5 A in 1 s?
b) What is the change in the magnetic flux through the other solenoid during this 1 s?
c) What is the induced EMF on the second solenoid?
d) What is the induced current on the second solenoid?
Example #1: Current in a Circuit with a Changing Magnetic Field
Practice: A square conducting wire of side length 4 cm is in a 2 T magnetic field. It rotates such that the angle of the magnetic field to the normal of the square increases from 30° to 60° in 2 s. What is the induced current on the wire if its resistance is 5 mΩ?