Lesson: Inductance Physics • 9th Grade

In this lesson, we will learn how to calculate the self-inductance of a conducting loop and the mutual inductance of a pair of conducting coils.

Lesson Plan

Students will be able to

understand that a current-carrying conducting coil induces a current in another coil due to the magnetic field produced by the first coil,
relate an induced emf to a rate of change of magnetic flux and to mutual inductance for two coils with equal number of turns, using the formulae and ,
understand that the magnetic field produced by a current-carrying loop induces a change in the current in the loop,
relate an induced rate of current change in a loop to its self-inductance and to the emf across it and the magnetic flux produced by the current, using the formulae and .

Lesson Video

Sample Question Videos

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01:39

Lesson Worksheet

Q1:

A loop of wire has a potential difference of 1.2 V across it. The loop has a self-inductance of 125 mH. How much time is required for the loop to increase the current through it by 0.25 A? Give your answer to two decimal places.

Q2:

A transformer with an iron core has a primary coil that has 15 turns and a secondary coil that has also 15 turns. In a time of 0.25 s, a potential difference of 12 V is applied across the primary coil, inducing a potential difference of 12 V across the secondary coil. What is the change of the magnetic flux through the iron core?

Q3:

A transformer with an iron core has a primary coil that has 75 turns and a secondary coil that has also 75 turns. The coils have a mutual inductance of 15 H. The current in the primary coil increases the current in the secondary coil at a rate of 1.25 A/s. What is the potential difference across the coils? Give your answer to one decimal place.