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For an A.C. given by I = 50 cos(100t + 45°) A, the value of Iᵣₘₛ = ______ A.

Asked in GUJCET 2017 · RMS and mean values

Answer: (4) 25√2

Step-by-step solution

Given: I = 50 cos(100t + 45°) A, so the peak value is I₀ = 50 A.

Idea: the rms value of a sinusoid depends only on its amplitude; the angular frequency (100 rad s⁻¹) and the phase (45°) do not matter.

Iᵣₘₛ = (I₀)/(√2) = (50)/(√2) = 25√2 A ≈ 35.4 A.

Why the other options are wrong

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