JEE Main 2026 Apr 6 Shift 1, Physics Q20: LR, CR, LCR Circuits

JEE Main2026Apr 6, Shift 1Physics

A LCR series circuit driven with $E_{rms} = 90$ V at frequency $f_{d} = 30$ Hz has resistance $R = 80 Ω$ , an inductance with inductive reactance $X_{L} = 20.0 Ω$ and capacitance with capacitive reactance $X_{C} = 80.0 Ω$ . The power factor of the circuit is ______.

A
$0.8$
B
$0.64$
C
$0.9$
D
$0.5$

Solution

Impedance: $Z = R^{2} + (X_{L} - X_{C})^{2} = 8 0^{2} + (20 - 80)^{2} = 6400 + 3600 = 100 Ω$ .

Power factor: $cos ϕ = \frac{R}{Z} = \frac{80}{100} = 0.8$ .

Concept behind this question

LR, CR, LCR CircuitsNotes, formulas and examples →

Practice more Physics

Concept-wise practice with instant solutions on Fundamenthol.

Start practicing →

JEE Main 2026 Apr 6 Shift 1, Physics Q20: LR, CR, LCR Circuits

Concept behind this question

More previous year questions on LR, CR, LCR Circuits

Practice more Physics