# Worksheet: Inductance

In this worksheet, we will practice calculating the self-inductance of a conducting loop and the mutual inductance of pair of conducting coils.

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?

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?

Q4:

A loop of wire carries a current of 180 mA. The magnetic flux produced by the current is 0.77 Wb. What is the self-inductance of the loop?

Q5:

A loop of wire has a self-inductance of 0.36 H. The current through the loop is 420 mA. What is the magnetic flux produced by the current?

Q6:

A circuit is powered by a 7.5 V source. The circuit carries a steady current of 1.4 A and contains an inductor with a self-inductance of 680 mH. When the voltage source is disconnected from the circuit, how much time passes before the current in the circuit becomes zero?

Q7:

The current induced in a loop of wire increases at 0.16 A/s. The loop has a self-inductance of 0.55 H. What is the potential difference across the loop?

Q8:

A transformer with an iron core has a primary coil with 25 turns and a secondary coil that also has 25 turns. The current in the primary coil increases the magnetic flux through the core by 0.15 Wb/s. The current in the secondary coil increases at 0.075 A/s. What is the mutual inductance of the coils?

Q9:

A transformer with an iron core has a primary coil with 45 turns and a secondary coil that also has 45 turns. The coils have a mutual inductance of 2.5 H. A current in the primary coil induces a potential difference of 2.2 V across the secondary coil in a time of 0.18 s. What is the current through the secondary coil after 0.18 s?

Q10:

A transformer consists of a primary coil and a secondary coil, each with the same number of turns, wrapped around an iron core. The coils have a mutual inductance of 32 mH. A current in the primary coil increases the magnetic flux through the core by 4.48 mWb. The current induced in the secondary coil is 1.4 A. How many turns does the coil have?