Ac Rms Current
Easyphysics
For i = I0 sin ωt, RMS current equals?
Select the correct option:
Solution
Incorrect! Answer:
I0/√2
- Definition of RMS: Root Mean Square (Irms) is the effective value of alternating current that produces the same heating effect as a DC current in the same resistance.
- Mathematical Definition: Irms=Average of i2.
- Calculation over Cycle:
- Average of sin2(ωt) over a full cycle is 1/2.
- Irms=I02×(1/2)=2I0.
- Numerical Result: Irms≈0.707⋅I0.
- Standard Usage: AC ammeters and voltmeters are calibrated to read RMS values.
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About This Question
- Subject
- physics
- Chapter
- em induction and ac
- Topic
- ac rms current
- Difficulty
- Easy
- Year
- 2025
Solution
Correct Answer:
I0/√2
- Definition of RMS: Root Mean Square (Irms) is the effective value of alternating current that produces the same heating effect as a DC current in the same resistance.
- Mathematical Definition: Irms=Average of i2.
- Calculation over Cycle:
- Average of sin2(ωt) over a full cycle is 1/2.
- Irms=I02×(1/2)=2I0.
- Numerical Result: Irms≈0.707⋅I0.
- Standard Usage: AC ammeters and voltmeters are calibrated to read RMS values.
This easy difficulty physics question is from the chapter em induction and ac, covering the topic of ac rms current. It appeared in the 2025 exam.
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