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JEE Main 2025 (24 Jan, Shift 1) · AC Basics: Peak, RMS & Average Values

AC Basics: Peak, RMS & Average Values question from JEE Main 2025 (24 Jan, Shift 1)

Q13JEE Main 2025 · 24 JAN · SHIFT 1Easy

AC Basics: Peak, RMS & Average Values

An alternating current is given by I=IAsin⁡ωt+IBcos⁡ωtI = I_A \sin \omega t + I_B \cos \omega t. The r.m.s current will be

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Answer: (b)

  1. Combine: I=IA2+IB2 sin⁡(ωt+ϕ)I = \sqrt{I_A^2 + I_B^2}\,\sin(\omega t + \phi), a single sinusoid.
  2. Peak I0=IA2+IB2I_0 = \sqrt{I_A^2 + I_B^2}
  3. Irms=I02=IA2+IB22I_{rms} = \frac{I_0}{\sqrt{2}} = \sqrt{\frac{I_A^2 + I_B^2}{2}}
  4. So the answer is (b).
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