Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
MHT CET 202621 AprilMorning Shift
Exam
MHT CET
Year
2026
Date
21 April
Shift
Morning Shift
Subject
Physics
Chapter
Alternating Current

MHT CET 2026 · 21 April · Morning Shift · Physics · Alternating Current

In series LCR circuit the alternating emf 'e' and the current 'i'...

In series LCR circuit the alternating emf 'e' and the current 'i' are given by the equations e=e0cos⁡ωte = e_0 \cos\omega t, i=i0sin⁡(ωt+π6)i = i_0 \sin\left(\omega t + \dfrac{\pi}{6}\right). The average power dissipated in the circuit over a one complete cycle of A.C is (cos⁡60=1/2\cos 60 = 1/2)

Options

  1. Ae0i02\dfrac{e_0 i_0}{2}
  2. Be0i04\dfrac{e_0 i_0}{4}
  3. C32e0i0\sqrt{\dfrac{3}{2}} e_0 i_0
  4. DZero

Correct answer

B. e0i04\dfrac{e_0 i_0}{4}

Step-by-step solution

The given equations for alternating emf and current are:

e=e0cos⁡ωt=e0sin⁡(ωt+π2)e = e_0 \cos\omega t = e_0 \sin\left(\omega t + \dfrac{\pi}{2}\right)

i=i0sin⁡(ωt+π6)i = i_0 \sin\left(\omega t + \dfrac{\pi}{6}\right)

The phase difference ϕ\phi between the emf and current is:

ϕ=π2−π6=π3=60∘\phi = \dfrac{\pi}{2} - \dfrac{\pi}{6} = \dfrac{\pi}{3} = 60^{\circ}

The average power dissipated over one complete cycle is given by:

Pavg=ermsirmscos⁡ϕP_{avg} = e_{rms} i_{rms} \cos\phi

Substituting the values of ermse_{rms}, irmsi_{rms}, and cos⁡ϕ\cos\phi:

Pavg=(e02)(i02)cos⁡60∘P_{avg} = \left(\dfrac{e_0}{\sqrt{2}}\right) \left(\dfrac{i_0}{\sqrt{2}}\right) \cos 60^{\circ}

Pavg=e0i02×12=e0i04P_{avg} = \dfrac{e_0 i_0}{2} \times \dfrac{1}{2} = \dfrac{e_0 i_0}{4}

Answer: e0i04\dfrac{e_0 i_0}{4}
Practice Alternating Current on Quantrex Academy →

More from Alternating Current

A step down transformer connected to an a.c. mains of 220 V is made to operate at 5.5 V… MHT CET Medical 2026Which phasor diagram represents LCR circuit at resonance? MHT CET Medical 2026For an R-L series circuit, the power factor is 3 2 , for R-L frequency f Hz. If the… MHT CET Medical 2026In an AC circuit, the current is I = 100 (5t) A. The value of I_ rms is MHT CET Medical 2026The ratio of power factor of purely resistive circuit to purely reactive circuit is ( 0^… MHT CET Medical 2026In an LCR series circuit, at resonance, MHT CET Medical 2026In an AC circuit, E and I are given by E = 150 (150t) V and I = 150 (150t + (π)/(3)) A.… MHT CET Medical 2026A series LCR circuit is connected across a source E of e.m.f. E=15 ( 50 π t- (π)/(3)).… MHT CET Medical 2026 Full Alternating Current list All MHT CET Medical PYQs