Exams › NEET › Physics

A coil of inductive reactance 31 Ω has a resistance of 8 Ω. It is placed in series with a condenser of capacitative reactance 25 Ω. The combination is connected to an a.c. source of 110 volt. The power factor of the circuit is

1. 0.64
2. 0.80
3. 0.33
4. 0.56

Correct answer: 0.64

Solution

The power factor is given by cos(ϕ) = R/Z, where Z is the impedance of the circuit. The impedance Z is calculated as Z = √(R² + (XL - XC)²). Substituting R = 8 Ω, XL = 31 Ω, and XC = 25 Ω, we get Z = √(8² + (31 - 25)²) = √(64 + 36) = √100 = 10 Ω. Thus, cos(ϕ) = 8/10 = 0.8.

Related NEET Physics questions

• The current flowing through the resistor in a series LCR a.c. circuit, is \( \boldsymbol{I}=\varepsilon / \boldsymbol{R} \) Now the inductor and capacitor are connected in parallel and joined in series with the resistor as shown in figure. The current in the circuit is now. (Symbols have their usual meaning)
• Which of the following will not increase voltage in a simple generator?
• With increase in frequency of an A.C. supply, the inductive reactance
• \( \ln \) an \( A C \) circuit, the instantanceous emf and current are given by \( e=100 \sin 30 t, i=\sin \left(30 t \frac{\pi}{4}\right) \) In one cycle of \( A C, \) the average power consumed by the circuit and the wattles current are, respectively
• The Joules heating effect for an electric heater in \( A . C \) and in D.C. circuit is
• A resistance \( (\boldsymbol{R})=12 \Omega ; \) inductance \( (L)=2 \) henry and capacitive reactance \( C=5 m F \) are connected in series to an ac generator, then:

⚔️ Practice NEET Physics free + battle 1v1 →