Ch 28: Induction and InductanceWorksheetSee all chapters
All Chapters
Ch 01: Units & Vectors
Ch 02: 1D Motion (Kinematics)
Ch 03: 2D Motion (Projectile Motion)
Ch 04: Intro to Forces (Dynamics)
Ch 05: Friction, Inclines, Systems
Ch 06: Centripetal Forces & Gravitation
Ch 07: Work & Energy
Ch 08: Conservation of Energy
Ch 09: Momentum & Impulse
Ch 10: Rotational Kinematics
Ch 11: Rotational Inertia & Energy
Ch 12: Torque & Rotational Dynamics
Ch 13: Rotational Equilibrium
Ch 14: Angular Momentum
Ch 15: Periodic Motion (NEW)
Ch 15: Periodic Motion (Oscillations)
Ch 16: Waves & Sound
Ch 17: Fluid Mechanics
Ch 18: Heat and Temperature
Ch 19: Kinetic Theory of Ideal Gasses
Ch 20: The First Law of Thermodynamics
Ch 21: The Second Law of Thermodynamics
Ch 22: Electric Force & Field; Gauss' Law
Ch 23: Electric Potential
Ch 24: Capacitors & Dielectrics
Ch 25: Resistors & DC Circuits
Ch 26: Magnetic Fields and Forces
Ch 27: Sources of Magnetic Field
Ch 28: Induction and Inductance
Ch 29: Alternating Current
Ch 30: Electromagnetic Waves
Ch 31: Geometric Optics
Ch 32: Wave Optics
Ch 34: Special Relativity
Ch 35: Particle-Wave Duality
Ch 36: Atomic Structure
Ch 37: Nuclear Physics
Ch 38: Quantum Mechanics
Induction Experiments
Magnetic Flux
Faraday's Law
Lenz's Law
Motional EMF
Mutual Inductance
Self Inductance
LR Circuits
LC Circuits
LRC Circuits

Concept #1: Lenz's Law

Practice: What is the direction of the induced current in the inner ring shown in the following figure? For this problem, consider the battery’s voltage as continuously INCREASING. Note: the arrow striking through the battery in the circuit diagram indicates that the voltage of the battery is variable (i.e. it can be changed).

Example #1: Bar Magnet vs Current Carrying Wire

Additional Problems
In the figure, a straight wire carries a steady current I. A bar is in contact with a pair of circular rails, and rotates about the straight wire. The induced current through the resistor R is: A) from b to a B) zero C) from a to b
A rectangular coil lies flat on a horizontal surface. A bar magnet is held above the center of the coil with its north pole pointing down. What is the direction of the induced current in the coil? A) counterclockwise B) clockwise C) No current in the coil D) None of the previous is correct
In Figure 1, two parallel wires carry a current I in opposite directions. A rectangular loop is midway between the wires. The current I is decreasing. The induced current through the resistor R is:  A) from b to a B) from a to b C) zero
In the figure, a bar magnet moves away from the solenoid. The induced current through the resistor R is: A) zero B) from b to a C) from a to b
In Figure 1, a battery supplies a steady current to the solenoid on the left. The two solenoids are moving toward each other. The induced current through the resistor R is: A) from a to b B) from b to a C) zero
A metal bar is pulled to the right perpendicular to a uniform magnetic field. The bar rides on parallel metal rails connected through a resistor, as shown in the figure below, so the apparatus makes complete circuit. Find the direction of the current induced in the circuit in two ways: a) By looking at the magnetic force on the charges in the moving bar. b) Using Lenz's Law
A long straight wire carries constant current I that is directed toward the left, as shown in the sketch. A small conducting loop is moving away from the wire with constant speed v. The current induced in the loop is A) zero B) clockwise C) counterclockwise
A bar magnet is dropped through a vertical copper tube and is observed to fall very slowly, despite the fact that mechanical friction between the magnet and the tube is negligible.  Which of following best explains the reason for this? A. The falling magnet magnetizes the copper pipe which causes the now permanent copper pipe magnet to attract the falling magnet thus causing the slower descent. B. The falling magnet is slowed by the Earth’s magnetic field. C. The changing flux of the falling magnet induces a magnetic field in the copper pipe, in the opposite direction of the bar magnet's field, which impedes the movement through the pipe. D. Friction and Air resistance cause the magnet to fall much slower than it would outside of the tube.
A single circular loop of wire in the plane of the page is perpendicular to a uniform magnetic field ~B directed into the page, as shown. If the magnitude of the magnetic field is decreasing, then the induced current in the wire loop is 1. counterclockwise around the loop. 2. directed upward out of the paper. 3. zero. (No current is induced.) 4. clockwise around the loop. 5. directed downward into the paper.