Question:
The potential across a generator is 125V when it is delivering 10A. When it delivers 30A the potential is 120V. What are the resistance of armature and induced e.m.f. ?
The potential across a generator is 125V when it is delivering 10A. When it delivers 30A the potential is 120V. What are the resistance of armature and induced e.m.f. ?
Updated On: Jul 2, 2022
- $5\Omega,127.5V$
- $0.25\Omega,127.5V$
- $2.5\Omega,120V$
- $5\Omega,130V$
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The Correct Option is B
Solution and Explanation
Using V = E - $ir$ , we get, 125 = E - 10r ....$(i)$
and 120 = E - 30r ...$(ii)$
Subtracting $(ii)$ from $(i)$, 5 = 20$r$ or $r$ = 0.25$\Omega$
from $(i)$ 125 = E - (10 $\times$ 0.25)
or E = 125 + 2.5 = 127.5 V
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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:-
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- 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
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- Φ = Magnetic flux (This is the amount of magnetic field present on the surface)
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Applications of Electromagnetic Induction
- Electromagnetic induction in AC generator
- Electrical Transformers
- Magnetic Flow Meter