Let us consider two solenoids \(A\) and \(B,\) made from the same magnetic material of relative permeability \(\mu_{r}\) and of equal area of cross-section. Length of \(A\) is twice that of \(B\) and the number of turns per unit length in \(A\) is half that of \(B.\) The ratio of self-inductances of the two solenoids, \(L_A:L_B\) is:
1. \(1:2\) 2. \(2:1\)
3. \(8:1\) 4. \(1:8\)
Subtopic:  Self - Inductance |
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Level 2: 60%+
NEET - 2024
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When the current in a certain inductor coil is \(5.0~\text{A}\) and is increasing at the rate of \(10.0~\text{A/s}\), the potential difference across the coil is \(140~\text{V}\). When the current is \(5.0~\text{A}\) and decreasing at the rate of \(10.0~\text{A/s}\), the potential difference is \(60~\text{V}\). The self-inductance of the coil is:
1. \(2~\text{H}\)
2. \(4~\text{H}\)
3. \(8~\text{H}\)
4. \(12~\text{H}\)

Subtopic:  Self - Inductance |
 55%
Level 3: 35%-60%
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The network shown in the figure is part of a complete circuit. If at a certain instant, the current \(I\) is \(5~\text{A}\) and it is decreasing at a rate of \(5\times 10^{3}~\text{A/s}\), then \(V_B-V_A\) is equal to: 

              

1. \(20~\text{V}\) 2. \(15~\text{V}\)
3. \(10~\text{V}\) 4. \(5~\text{V}\)
Subtopic:  Self - Inductance |
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Level 3: 35%-60%
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A coil of self-inductance \(L\) is connected in series with a bulb \(B\) and an AC source. The brightness of the bulb decreases when:
1. number of turns in the coil is reduced.
2. a capacitance of reactance \(X_C = X_L\) is included in the same circuit.
3. an iron rod is inserted in the coil.
4. frequency of the AC source is decreased.
Subtopic:  Self - Inductance |
 68%
Level 2: 60%+
AIPMT - 2013
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The inductance of a closed-packed coil of 400 turns is 8 mH. A current of 5 mA is passed through it. The magnetic flux through each turn of the coil is approximately-

1.  0.1μ0Wb                     

2.  0.2μ0Wb

3.  1.0μ0Wb                     

4.  2.0μ0Wb

Subtopic:  Self - Inductance |
 67%
Level 2: 60%+
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The magnetic energy stored in an inductor of inductance \(4~\mu\text{H}\) carrying a current of \(2~\text{A}\) is:
1. \(8~\mu \text{J}\)
2. \(4~\mu \text{J}\)
3. \(4~\text{mJ}\)
4. \(8~\text{mJ}\)
Subtopic:  Self - Inductance |
 78%
Level 2: 60%+
NEET - 2023
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The magnetic potential energy stored in a certain inductor is \(25~\text{mJ},\) when the current in the inductor is \(60~\text{mA}.\) This inductor is of inductance:
1. \(0.138~\text H\)
2. \(138.88~\text H\)
3. \(1.389~\text H\)
4. \(13.89~\text H\)

Subtopic:  Self - Inductance |
 71%
Level 2: 60%+
NEET - 2018
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The current \((I)\) in the inductance is varying with time \((t)\) according to the plot shown in the figure. 


Which one of the following is the correct variation of voltage with time in the coil?
1. 2.
3. 4.
Subtopic:  Self - Inductance |
 74%
Level 2: 60%+
AIPMT - 2012
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The current in an inductor of self-inductance \(4~\text{H}\) changes from \(4~ \text{A}\) to \(2~\text{A}\) in \(1~ \text s\). The emf induced in the coil is:
1. \(-2~\text{V}\)
2. \(2~\text{V}\)
3. \(-4~\text{V}\)
4. \(8~\text{V}\)

Subtopic:  Self - Inductance |
 85%
Level 1: 80%+
NEET - 2022
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An inductor coil of self-inductance \(10~\text{H}\) carries a current of \(1~\text{A}\). The magnetic field energy stored in the coil is:
1. \(10~\text{J}\) 2. \(2.5~\text{J}\)
3. \(20~\text{J}\) 4. \(5~\text{J}\)
Subtopic:  Self - Inductance |
 85%
Level 1: 80%+
NEET - 2022
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