EASY
12th CBSE
IMPORTANT
Earn 100

Calculate the impedance of a coil of resistance 3Ω and reactance 4Ω.

Important Questions on Alternating Current and Electrical Machines

MEDIUM
12th CBSE
IMPORTANT
PHYSICS A Reference Book for Class 12 Volume 2>Chapter 1 - Alternating Current and Electrical Machines>Problems For Practice>Q 2
An inductance coil has a resistance of 100 ohm. When a.c. signal of frequency 1000Hz is applied to the coil, the applied voltage leads the current by 45°. Calculate the self-inductance of the coil.
HARD
12th CBSE
IMPORTANT
PHYSICS A Reference Book for Class 12 Volume 2>Chapter 1 - Alternating Current and Electrical Machines>Problems For Practice>Q 3
An a.c. source of 100V r.m.s., 50Hz is connected across a 20Ω resistor and 2mH inductor in series Calculate (i) impedance of the circuit and (ii) r.m.s. current in the circuit.
HARD
12th CBSE
IMPORTANT
PHYSICS A Reference Book for Class 12 Volume 2>Chapter 1 - Alternating Current and Electrical Machines>Problems For Practice>Q 4
A 100V, 50Hz a.c. source is connected to a series combination of an inductance of 100mH and a resistance of 20Ω. Calculate the magnitude and phase of the current.
HARD
12th CBSE
IMPORTANT
PHYSICS A Reference Book for Class 12 Volume 2>Chapter 1 - Alternating Current and Electrical Machines>Problems For Practice>Q 5
A current of 11A flows through a coil, when connected to a 110V d.c. source. When 110V a.c. of 50Hz is applied to the coil, only 0.5A current flows. Calculate the (i) resistance (ii) impedance and (iii) inductance of the coil.
HARD
12th CBSE
IMPORTANT
PHYSICS A Reference Book for Class 12 Volume 2>Chapter 1 - Alternating Current and Electrical Machines>Problems For Practice>Q 6
An arc takes a current of 10A at 80V. Find the inductance, which should be put in series to work the arc from 220V, 50Hz supply.
MEDIUM
12th CBSE
IMPORTANT
PHYSICS A Reference Book for Class 12 Volume 2>Chapter 1 - Alternating Current and Electrical Machines>Problems For Practice>Q 7

A current of 2.0A is flowing in the LR-circuit shown in figure. Find the voltage across the a.c. source and the impedance of the circuit.
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MEDIUM
12th CBSE
IMPORTANT
PHYSICS A Reference Book for Class 12 Volume 2>Chapter 1 - Alternating Current and Electrical Machines>Problems For Practice>Q 8

Calculate the impedance and the rms current in the a.c. circuit shown in figure.
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MEDIUM
12th CBSE
IMPORTANT
PHYSICS A Reference Book for Class 12 Volume 2>Chapter 1 - Alternating Current and Electrical Machines>Problems For Practice>Q 9

The virtual current in the a.c. circuit shown in Figure, is 1.0A. Find (i) virtual voltage across the coil L (ii) impedance of the circuit and (iii) reactance of the coil.

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