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Saturday, 31 October

JEE Main 2021 · PhysicsNumerical answerNumerical valueMediumMulti-step

JEE Main 25 July 2021, Shift 2, Physics Q25

Question 25 of 90 in this shift, Physics question 25 of 30, Section B.

Two circuits are shown in the figure (a) & (b). At a frequency of __________ rad/s the average power dissipated in one cycle will be same in both the circuits.

The figure, in words

Figure (a): a 5 ohm resistor R in series with a 220 V AC source. Figure (b): a 40 μ\muF capacitor C, a 5 ohm resistor R and a 0.1 H inductor L in series with a 220 V AC source.

Official answer

500

NTA final key.

Chapter
Alternating Current
Topic
LCR Resonance
Idea tested
Resonant Frequency Calculation

Same idea in other shifts

Asked 9× in all
  1. 5 Apr 2026, Shift 2 · Q48A series LCR circuit with R=20 ΩR=20\ \Omega, L=1.6L=1.6 H and C=40 μFC=40\ \mu\mathrm{F} is connected to a variable frequency a.c. source. The…EasyNumerical value
  2. 6 Apr 2024, Shift 2 · Q59For a given series LCR circuit it is found that maximum current is drawn when value of variable capacitance is 2.5 nF. If resistance of…EasyNumerical value
  3. 1 Feb 2024, Shift 1 · Q43In series LCR circuit, the capacitance is changed from C to 4C. To keep the resonance frequency unchanged, the new inductance should be :EasySingle correct
  4. 25 Jul 2022, Shift 1 · Q42To increase the resonant frequency in series LCR circuit,EasySingle correct
  5. 28 Jun 2022, Shift 1 · Q60A telegraph line of length 100 km has a capacity of 0.01 μ\muF/km and it carries an alternating current at 0.5 kilo cycle per second. If…EasyNumerical value
  6. 29 Jun 2022, Shift 2 · Q60An inductor of 0.5 mH, a capacitor of 200 μF and a resistor of 2 Ω are connected in series with a 220 VV ac source. If the current is in…EasyNumerical value
  7. 25 Feb 2021, Shift 1 · Q27A transmitting station releases waves of wavelength 960 m. A capacitor of 2.56 μ2.56\ \muF is used in the resonant circuit. The self…EasyNumerical value
  8. 26 Feb 2021, Shift 2 · Q18Find the peak current and resonant frequency of the following circuit (as shown in figure).MediumDiagram basedHas a figure

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.