250+ TOP MCQs on Schering Bridge and Answers

Electrical Measurements & Measuring Instruments Multiple Choice Questions on “Schering Bridge”.

1. Schering bridge is one of the most widely used AC bridges.
a) True
b) False
Answer: a
Clarification: Schering bridge is an AC bridge used for the measurement of unknown capacitance, dielectric loss and power factor. It is one of the most commonly used AC bridges.

2. Schering bridge is used for _________
a) low voltages only
b) low and high voltages
c) high voltages only
d) intermediate voltages only
Answer: b
Clarification: Schering bridge is used for both low as well as high voltages. A particular bridge connection is used for low voltage. High voltages employ the use of a different type of Schering bridge.

3. Power factor of a Schering bridge is _________
a) p.f. = sin∅_x = ^Z_x⁄_{R_x}
b) p.f. = cot∅_x = ^R_x⁄_{Z_x}
c) p.f. = cos∅_x = ^R_x⁄_{Z_x}
d) p.f. = tan∅_x = ^R_x⁄_{Z_x}
Answer: c
Clarification: The power factor of the RC combination in a Schering bridge is given by the relation p.f. = cos∅_x = ^R_x⁄_{Z_x}.
where,
R_x is the series resistance
Z_x is the series impedance comprising of Rx and C_x.

4. For phase angles close to 90°, the power factor of the bridge is _________
a) p.f. = ωR_x
b) p.f. = ωC_x
c) p.f. = R_x C_x
d) p.f. = ωR_x C_x
Answer: d
Clarification: When phase angle reaches 90°, reactance equals the impedance and the power factor of the bridge is calculated using the relation,

5. For a series RC circuit, what is δ?
a) voltage between series RC combination and C
b) voltage between series RC combination
c) voltage across C
d) voltage across R
Answer: a
Clarification: In a series RC circuit, δ refers to the angle between the series combination of R_x, C_x and the voltage across the capacitance C_x. δ is also known as the loss angle.

6. What is the expression for the loss angle?
a) tan⁡ δ = ωR₄
b) tan⁡ δ = ωR₄ C₄
c) tan⁡ δ = ωC₄
d) tan⁡ δ = R₄ C₄
Answer: b
Clarification: The expression for the loss angle can be computed as the ratio of the tangent of the voltage drop across resistance R_x to the voltage drop across the capacitance C_x.

7. Quality factor is given by which of the following expression?
a) Q = ¹⁄_R
b) Q = R
c) Q = ^X⁄_R
d) Q = XR
Answer: c
Clarification: The quality factor the Schering bridge circuit is defined as Q = ^X⁄_R.
where, X = ¹⁄_wC is the capacitive impedance.

8. Dissipation factor is the reciprocal of quality factor.
a) True
b) False
Answer: a
Clarification: Dissipation factor for a circuit is defined as the reciprocal of the quality factor.
It is given by the expression Q = ¹⁄_wCR. It basically provides information about the quality of a capacitor.

9. Commercial Schering bridge can be used for the measurement of capacitances from _____________
a) 10pF to 0.1nF
b) 100pF to 1μF
c) 50nF to 10mF
d) 25mF to 5F
Answer: b
Clarification: Commercial Schering bridges are used for the measurement of capacitances in the range of a few pico farads to a few micro farads. Accuracy varies in the range of –2% to +2%.

10. A Schering bridge can be used for the ______________
a) measuring voltages
b) measuring currents
c) testing capacitors
d) protecting the circuit from temperature rises
Answer: c
Clarification: A Schering bridge can be used with both low voltage as well as high voltages. A Schering bridge is basically used for the measurement of small capacitances at low voltages with high precision.