(A) The power factor in an $AC$ circuit is defined as the cosine of the phase angle $\phi$ between the voltage and the current. It is given by $\cos \

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Power factor is $\cos \phi$,where $\phi$ is the phase difference between voltage and current.

(A) The power factor in an $AC$ circuit is defined as the cosine of the phase angle $\phi$ between the voltage and the current. It is given by $\cos \phi = R/Z$,where $R$ is the resistance and $Z$ is the impedance of the circuit.In an $AC$ circuit,the voltage and current are generally not in phase. The relationship is expressed as $V = V_m \sin(\omega t)$ and $I = I_m \sin(\omega t - \phi)$,where $\phi$ represents the phase difference.

Class 12 Physics Alternating Current Power in AC and Power Factor

Medium

What is power factor and voltage-current relationship in an $AC$ circuit?

A
Power factor is $\cos \phi$,where $\phi$ is the phase difference between voltage and current.
B
Power factor is $\sin \phi$,where $\phi$ is the phase difference between voltage and current.
C
Power factor is $\tan \phi$,where $\phi$ is the phase difference between voltage and current.
D
Power factor is $\cot \phi$,where $\phi$ is the phase difference between voltage and current.

Explore More

Browse All

Question Bank

All Subjects

Class 12 Questions

Class 12

Physics Questions

Chapter

Alternating Current

Subtopic

Power in AC and Power Factor

In an $ac$ circuit,$V$ and $I$ are given by $V = 100 \sin(100t) \text{ V}$ and $I = 100 \sin(100t + \frac{\pi}{3}) \text{ mA}$. The power dissipated in the circuit is ....... $W$.

Medium

View Solution

An e.m.f. $e=E_0 \cos \omega t$ is applied to a circuit containing $L, C$ and $R$ in series where $X_L=3 R$ and $X_C=R$. The average power dissipated in the circuit is

MediumMHT CET 2025

View Solution

In an $AC$ circuit $E = 200 \sin(50t) \text{ V}$ and $I = 100 \sin(50t + \frac{\pi}{3}) \text{ mA}$. The power dissipated in the circuit is (Given: $\sin 30^{\circ} = \cos 60^{\circ} = 0.5$,$\sin 60^{\circ} = \cos 30^{\circ} = \frac{\sqrt{3}}{2}$) (in $watt$)

EasyMHT CET 2024

View Solution

Assertion $(A):$ If the frequency of the applied $AC$ is doubled, then the power factor of a series $R-L$ circuit decreases.
Reason $(R):$ Power factor of a series $R-L$ circuit is given by $\cos \theta = \frac{2R}{\sqrt{R^2 + \omega^2 L^2}}$.

MediumAIIMS 2015

View Solution

$A$ series $LCR$ circuit is connected to an a.c. source of $230 \ V, 50 \ Hz$. The circuit contains a resistance of $80 \ \Omega$,an inductor having inductive reactance $70 \ \Omega$,and a capacitor of capacitive reactance $130 \ \Omega$. The power factor of the circuit is $x$. The value of $x$ is

MediumMHT CET 2025

View Solution

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial

For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free

For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo

What is power factor and voltage-current relationship in an $AC$ circuit?

Similar Questions

In an $ac$ circuit,$V$ and $I$ are given by $V = 100 \sin(100t) \text{ V}$ and $I = 100 \sin(100t + \frac{\pi}{3}) \text{ mA}$. The power dissipated in the circuit is ....... $W$.

An e.m.f. $e=E_0 \cos \omega t$ is applied to a circuit containing $L, C$ and $R$ in series where $X_L=3 R$ and $X_C=R$. The average power dissipated in the circuit is

In an $AC$ circuit $E = 200 \sin(50t) \text{ V}$ and $I = 100 \sin(50t + \frac{\pi}{3}) \text{ mA}$. The power dissipated in the circuit is (Given: $\sin 30^{\circ} = \cos 60^{\circ} = 0.5$,$\sin 60^{\circ} = \cos 30^{\circ} = \frac{\sqrt{3}}{2}$) (in $watt$)

Assertion $(A):$ If the frequency of the applied $AC$ is doubled, then the power factor of a series $R-L$ circuit decreases.Reason $(R):$ Power factor of a series $R-L$ circuit is given by $\cos \theta = \frac{2R}{\sqrt{R^2 + \omega^2 L^2}}$.

$A$ series $LCR$ circuit is connected to an a.c. source of $230 \ V, 50 \ Hz$. The circuit contains a resistance of $80 \ \Omega$,an inductor having inductive reactance $70 \ \Omega$,and a capacitor of capacitive reactance $130 \ \Omega$. The power factor of the circuit is $x$. The value of $x$ is

Vedclass Test Series

Exam Paper Generator

Online Exam Module

Assertion $(A):$ If the frequency of the applied $AC$ is doubled, then the power factor of a series $R-L$ circuit decreases.
Reason $(R):$ Power factor of a series $R-L$ circuit is given by $\cos \theta = \frac{2R}{\sqrt{R^2 + \omega^2 L^2}}$.