When the current in a coil changes from \(5~\text{A}\) to \(2~\text{A}\) in \(0.1~\text{s},\) the average voltage of \(50~\text{V}\) is produced. The self-inductance of the coil is:
1. \(1.67~\text{H}\)
2. \(6~\text{H}\)
3. \(3~\text{H}\)
4. \(0.67~\text{H}\)
Subtopic:  Self - Inductance |
From NCERT
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The total number of turns and the cross-sectional area of a solenoid are fixed. However, its length \(L\) is varied by adjusting the separation between the windings. The inductance of the solenoid will be proportional to:

1. \(L\) 2. \(L^2\)
3. \(\dfrac{1}{L^2}\) 4. \(\dfrac{1}{L}\)
Subtopic:  Self - Inductance |
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The current in a coil of self-inductance \(2.0~\text{H}\) is increasing according to equation \(I=2 \sin t^2~\text{A}\). The amount of energy spent during the period when the current changes from \(0\) to \(2~\text{A}\) is:
1. \(4~\text{J}\)
2. \(3~\text{J}\)
3. \(1~\text{J}\)
4. \(6~\text{J}\)
Subtopic:  Self - Inductance |
From NCERT
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A \(10~\Omega\), \(20~\text{mH}\) coil carrying constant current is connected to a battery of \(20~\text{V}\) through a switch. When the switch is opened, the current becomes zero in \(100~\mu \text{s}\). The average emf induced in the coil is:
1. \(100~\text{V}\)
2. \(250~\text{V}\)
3. \(400~\text{V}\)
4. \(550~\text{V}\)
Subtopic:  Self - Inductance |
From NCERT
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A coil of inductance \(1\) H and resistance \(100~\Omega\) is connected to a battery of \(6\) V. Determine approximately:
I. The time elapsed before the current acquires half of its steady–state value.
II. The energy stored in the magnetic field associated with the coil at an instant \(15\) ms after the circuit is switched on.
(Given: \(\mathrm{ln}2 = 0.693, e^{\frac{-3}{2}}= 0.25\))
1. \(t =10~\text{ms}; U = 2~\text{mJ}\)
2. \(t =10~\text{ms}; U = 1~\text{mJ}\)
3. \(t =7~\text{ms}; U = 1~\text{mJ}\)
4. \(t =7~\text{ms}; U = 2~\text{mJ}\)
Subtopic:  Self - Inductance |
From NCERT
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In a coil, the current changes from \(-2\) A to \(+2\) A in \(0.2\) s and induces an emf \(0.1\) V. The self-inductance of the coil is :
1. \(4\) mH
2. \(5\) mH
3. \(2.5\) mH
4. \(1\) mH
Subtopic:  Self - Inductance |
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