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The ratio of time constant in charging and discharging in the circuit shown in the figure is 

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Important Questions on Electromagnetic Induction

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Chapterwise/Topicwise Daily Practice Problems (DPP) Magnetism and Electromagnetic Induction NEET>Chapter 3 - Electromagnetic Induction>LR Circuit>Q 88
The time constant of an inductance coil is 2.0×10-3 s. When a 90 Ω resistance is joined in series, the time constant becomes 0.5×10-3 s. The inductance and resistance of the coil, respectively, are,
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Chapterwise/Topicwise Daily Practice Problems (DPP) Magnetism and Electromagnetic Induction NEET>Chapter 3 - Electromagnetic Induction>LR Circuit>Q 89

For the circuit shown, which of the following statement is correct?

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Chapterwise/Topicwise Daily Practice Problems (DPP) Magnetism and Electromagnetic Induction NEET>Chapter 3 - Electromagnetic Induction>LR Circuit>Q 90

The network shown in the figure is a part of a complete circuit. If at a certain instant, the current I is 5 A and is decreasing at the rate of 103 A/s, then VB -VA = ____ V.

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Chapterwise/Topicwise Daily Practice Problems (DPP) Magnetism and Electromagnetic Induction NEET>Chapter 3 - Electromagnetic Induction>AC Generator and Motor>Q 91
A dynamo dissipates 20 W when it supplies a current of 4 A through it. If the terminal potential difference is 220 V, then, calculate the emf produced.
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Chapterwise/Topicwise Daily Practice Problems (DPP) Magnetism and Electromagnetic Induction NEET>Chapter 3 - Electromagnetic Induction>AC Generator and Motor>Q 92
An electric motor operating on a 50 V DC supply draws a current of 12 A. If the efficiency of the motor is 30%, estimate the resistance of the windings of the motor.
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Chapterwise/Topicwise Daily Practice Problems (DPP) Magnetism and Electromagnetic Induction NEET>Chapter 3 - Electromagnetic Induction>AC Generator and Motor>Q 93
The armature of a DC motor has 20 Ω resistance. It draws a current of 1.5 A when run by the 220 V DC supply. The value of back emf induced in it will be 
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Chapterwise/Topicwise Daily Practice Problems (DPP) Magnetism and Electromagnetic Induction NEET>Chapter 3 - Electromagnetic Induction>AC Generator and Motor>Q 94
A simple electric motor has an armature resistance of 1 Ω and runs from a DC source of 12 V. When unloaded, it draws a current of 2 A. When a certain load is connected, its speed becomes one-half of its unloaded value. Then, the current it draws (in amperes) is,
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Chapterwise/Topicwise Daily Practice Problems (DPP) Magnetism and Electromagnetic Induction NEET>Chapter 3 - Electromagnetic Induction>AC Generator and Motor>Q 95
If the rotational velocity of a dynamo armature is doubled then, the induced emf will,