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Self-induced emf or self-inductance from a change of current

This type of question, asked 4 times: 26 Jun 2022, 15 Apr 2023, 5 Apr 2024, 6 Apr 2024. All 4 questions below, oldest first.

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  1. Question 1

    26 Jun 2022

    25
    A 10Ω,20mH10\Omega,20mH coil carrying constant current is connected to a battery of 20 V20\text{ }V through a switch. When the switch is opened, the current becomes zero in 100μs100\mu s. The average emf induced in the coil is ____\_\_\_\_ V.

  2. Question 2

    15 Apr 2023

    11
    A 12 V12\text{ }V battery connected to a coil of resistance 6 Ω\Omega through a switch, drives a constant current in the circuit. The switch is opened in 1 ms1\text{ }ms. The emf induced across the coil is 20 V20\text{ }V. The inductance of the coil is:

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  3. Question 3

    5 Apr 2024

    120
    The current in an inductor is given by I=(3t+8)I = (3t + 8) where tt is in second. The magnitude of induced emf produced in the inductor is 12mV12mV. The self-inductance of the inductor is ____\_\_\_\_ mHmH.

  4. Question 4

    6 Apr 2024

    99
    In a coil, the current changes from −2 A- 2\text{ }A to +2 A+ 2\text{ }A in 0.2 s0.2\text{ }s and induces an emf of 0.1 V0.1\text{ }V. The self-inductance of the coil is:

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