JEE Main 2021 · PhysicsMultiple choiceSingle correctEasyCalculation

JEE Main 18 March 2021, Shift 2, Physics Q13

Question 13 of 90 in this shift, Physics question 13 of 30, Section A.

In a series LCR circuit, the inductive reactance (

X_L

) is 10

\Omega

and the capacitive reactance (

X_C

) is 4

\Omega

. The resistance (R) in the circuit is 6

\Omega

. The power factor of the circuit is :

(1) $\frac{1}{\sqrt{2}}$ Official answer
(2) $\frac{\sqrt{3}}{2}$
(3) $\frac{1}{2}$
(4) $\frac{1}{2\sqrt{2}}$

Official answer

Option 1

NTA final key.

Chapter: Alternating Current
Topic: Phasor Diagrams
Idea tested: Power Factor from Phasors

Same idea in other shifts

Asked 9× in all

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30 Jan 2024, Shift 1 · Q43A series L.R circuit connected with an ac source $E = (25\sin 1000\,t)$ V has a power factor of $\frac{1}{\sqrt{2}}$ . If the source of emf…MediumSingle correct
31 Jan 2024, Shift 2 · Q43An AC voltage $V=20\sin 200\pi t$ is applied to a series LCR circuit which drives a current $I=10\sin\left(200\pi t+\frac{\pi}{3}\right)$ .…EasySingle correct
26 Jul 2022, Shift 1 · Q37In a series LR circuit $X_L = R$ and power factor of the circuit is $P_1$ . When capacitor with capacitance C such that $X_L = X_C$ is put…EasySingle correct
30 Jul 2022, Shift 2 · Q12In an A.C circuit , V & I are given by V = 250 sin (100 t) volt and I = 10 sin (100 t + $\frac{\pi}{3}$ ) A respectively The power…EasySingle correct
27 Aug 2021, Shift 2 · Q22An ac circuit has an inductor and a resistor of resistance R in series, such that $X_L=3\ R$ . Now, a capacitor is added in series such…MediumNumerical value
6 Sep 2020, Shift 2 · Q23In a series LR circuit, power of 400 W is dissipated from a source of 250 V, 50 Hz. The power factor of the circuit is 0.8. In order to…MediumNumerical value

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. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.