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Concepts Of Physics MCQ Edition [Volume 2]PhysicsAlternating Current

A resistor carries a constant current of 2.8 A . The rms value of this current is

Options

  1. Aapproximately 2.0 A
  2. Bundefined for a direct current
  3. C2.8 A
  4. D1.4 A

Correct answer

C. 2.8 A

Step-by-step solution

The root mean square (rms) value of a current I(t) over a time interval T is given by I_ rms = 1 T ₀^ T I² dt . For a constant current, I(t) = I₀ for all t . Substituting this into the formula, we get I_ rms = 1 T ₀^ T I₀² dt = I₀² = I₀ . Given that the constant current is 2.8 A , its rms value is also 2.8 A .

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