Question:
If the power factor changes from $\frac{1}{2}\,to\,\frac{1}{4}$ ,then what is the increase in impedance in A.C. ?
If the power factor changes from $\frac{1}{2}\,to\,\frac{1}{4}$ ,then what is the increase in impedance in A.C. ?
Updated On: Jul 6, 2022
- 0.2
- 0.5
- 0.25
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The Correct Option is D
Solution and Explanation
cos $\theta \propto \frac{1}{Z} ; \frac{Z_1}{Z_2} = \frac{cos \, \theta_1}{cos \, \theta_2} = \frac{1/4}{1/2} = \frac{1}{2} \, z_2 = 2 z_1$
Percentage change = $\frac{2 Z_1 - Z_1}{Z_1} \times 100 $= 100 %.
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Concepts Used:
Electromagnetic Induction
Electromagnetic Induction is a current produced by the voltage production due to a changing magnetic field. This happens in one of the two conditions:-
- When we place the conductor in a changing magnetic field.
- When the conductor constantly moves in a stationary field.
Formula:
The electromagnetic induction is mathematically represented as:-
e=N × d∅.dt
Where
- e = induced voltage
- N = number of turns in the coil
- Φ = Magnetic flux (This is the amount of magnetic field present on the surface)
- t = time
Applications of Electromagnetic Induction
- Electromagnetic induction in AC generator
- Electrical Transformers
- Magnetic Flow Meter