Ch 3 - L2 Inductance

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?

• 0.01s

• 0.02s

• 0.03s

• 0.04s

What is the reason for the slow rate of change of the current intensity in a solenoid?

• The solenoid emitting electromagnetic radiation

• The solenoid always having a high resistance

• Self-induced current opposes changes to the original current

• The production of magnetic flux around the solenoid

• less than 0.8 A

• equal to 0.8 A

• greater than 0.8 A

• equal to zero

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?

• 40

• 10

• 20

• 32

The following graph represents how the electric current intensity (𝐼) in a solenoid changes with time. The self-induction coefficient of the solenoid is 30 mH. What is the induced emf in the solenoid in the time period bc?

• 0 V

• 12 V

• 10 V

• 24 V

• 0.04 H

• 0.02 H

• 0.01 H

• 0.03 H

The mutual inductance between these two coils equals ..........

• 1 H

• 4 H

• 0.25 H

• 2 H

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?

• 0.25 A
• 3.2 A
• 0.88 A
• 0.16 A

A transformer with an iron core has a primary coil that has 75 turns and a secondary coil that also has 75 turns. The coils have a mutual inductance of 15 H.The change in the current in the primary coil changes the current in the secondary coil at a rate of 1.25 A/s. What is the potential difference across the coils?

• 18.8 V

• 12.75 V
• 30.50 V
• 5.25 V

A solenoid has a self-inductance of 0.3 H. If the core is filled with iron, the solenoid’s self-induction coefficient then

• becomes greater than 0.3 H

• becomes less than 0.3 H

• becomes equal to 0.3 H

• cannot be determined