An A.C varies with time (t) sec as I=4 sin(200πt), the r.m.s value of current in "A" is:
Correct answer: C. 4/√2
- A. 2
- B. 4√2
- C. 4/√2
- D. 2/√2
Explanation
The root mean square (r.m.s.) value of an alternating current is derived from its peak value using the formula Irms = Ipeak / √2. In this case, the peak current is given as 4 A (from the equation I=4 sin(200πt)). Thus, the calculation for the r.m.s. value is:Irms = 4 / √2 = 4/√2 A.Option A (2) is incorrect because it does not reflect the proper calculation. Option B (4√2) incorrectly applies multiplication instead of division. Option D (2/√2) also misrepresents the peak value, leading to an inaccurate result.
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About Alternating Current
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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