If the instantaneous current in a circuit is given by I=2cos(wt+θ) ampere, the rms value of the current is
Correct answer: C. √2 A
- A. 2A
- B. 2√2 A
- C. √2 A
- D. zero
Explanation
To find the rms value of the given current, we need to use the relationship between the rms value and the peak value of an AC current. The rms value of a current waveform I(t) is given by Irms =Ipeak/√2. In the given current equation I=2cos(wt+θ), the peak value of the current is Ipeak =2 A. Therefore, the rms value is Irms = (2/√2 ) = √2 A
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Alternating current varies periodically, so phase relationships become essential when current passes through a resistor, capacitor or inductor. The chapter distinguishes resistance from capacitive and inductive reactance, explains phase lead and lag, and connects changing electric and magnetic fields with the production and properties of electromagnetic waves.
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