Explore topic-wise MCQs in Physics.

This section includes 10 Mcqs, each offering curated multiple-choice questions to sharpen your Physics knowledge and support exam preparation. Choose a topic below to get started.

1.

Which among the following is the correct expression for finding capacitive reactance for an ac circuit containing capacitor only?

A. Xc = 2πf
B. Xc = \(\frac {1}{2πfC}\)
C. Xc = 2πfC
D. Xc = \(\frac {2πf}{C}\)
Answer» C. Xc = 2πfC
2.

A 1.50 μF capacitor is connected to a 220 V, 50 Hz source. If the frequency is doubled, what happens to the capacitive reactance?

A. Remains the same
B. Doubled
C. Halved
D. Becomes zero
Answer» D. Becomes zero
3.

What will be the reactance of a capacitor at 150 Hz, if it has a reactance of 200 Ω at 50 Hz?

A. 67 Ω
B. 40 Ω
C. 150 Ω
D. 60 Ω
Answer» B. 40 Ω
4.

Calculate the rms value of current in the circuit wherein an 80 μF capacitor is connected to a 100 V, 80 Hz ac supply.

A. 4 A
B. 2 A
C. 7 A
D. 50 A
Answer» B. 2 A
5.

The capacitive reactance varies directly with the frequency.

A. True
B. False
Answer» C.
6.

Give the SI unit of capacitive reactance.

A. Am
B. Ω
C. Ωm
D. A
Answer» D. A
7.

How will the capacitive reactance be affected if the frequency is doubled?

A. Doubled
B. Insignificant
C. Remains the same
D. Halved
Answer» E.
8.

What is the capacitive reactance of a 5 μF capacitor when it is a part of a circuit whose frequency is 50 Hz?

A. 636.6 Ω
B. 1636.6 Ω
C. 2636.6 Ω
D. 4636.6 Ω
Answer» B. 1636.6 Ω
9.

A capacitor of capacitance 10 μF is connected to an oscillator giving an output voltage, E = 10 sin ωt volt. If ω = 10 rad s-1, find the peak current in the circuit.

A. 197 mA
B. 1 mA
C. 179 mA
D. 5 mA
Answer» C. 179 mA
10.

A 1.5 μF capacitor is connected to a 220 V, 50 Hz source. Find the capacitive reactance in the circuit.

A. 2120 Ω
B. 21.2 Ω
C. 212 Ω
D. 2.12 Ω
Answer» D. 2.12 Ω