1. Value of unknown resistance is found by using which of the following relation?
a) Rx = \(\frac{R_1 R_3}{R_2}\)
b) Rx = \(\frac{R_2 R_1}{R_3}\)
c) Rx = \(\frac{R_2 R_3}{R_1}\)
d) Rx = \(\frac{R_2}{R_1}\)
Explanation: The inductance comparison bridge mainly consists of pure resistances in its ratio arm. The value of unknown resistance is given by the relation Rx = \(\frac{R_2 R_3}{R_1}\).
2. The value of unknown inductance is found by using which of the following relation?
a) Lx = \(\frac{R_1 L_3}{R_2}\)
b) Lx = \(\frac{R_2}{R_1}\)
c) Lx = \(\frac{L_3}{R_1}\)
d) Lx = \(\frac{R_2 L_3}{R_1}\)
Explanation:At balance condition in an inductance comparison bridge, the value of unknown inductance is found by using the relation Lx = \(\frac{R_2 L_3}{R_1}\).
3. Inductance control is obtained by _________
a) using R2
b) using R1
c) using R3
d) using Lx
Explanation:In an inductance comparison bridge, the resistance R2 and R3 are variable. The value of resistance R2 is varied so as to control the inductance of the bridge.
4. Bridge depends on frequency.
a) True
b) False
Explanation: In an inductance comparison bridge, the balance equation is independent of frequency. As a result the bridge balance condition remains unaffected by variation in the value of frequency
5. Bridge can be used at audio frequency.
a) True
b) False
Explanation: An inductance comparison bridge can be used for measurement of unknown inductance at a wide range of audio frequencies in the order of a few Hz to KHz
6. Bridge is used for the measurement of _________
a) high Q factor
b) medium Q factor
c) low Q factor
d) very low Q factor
Explanation:The inductance comparison bridge is used for the measurement of low Q factor values of the order of 1 to 10. It cannot be used for the measurement of Q factors below 1. As a result, the bridge is used for the measurement of medium Q factor values
7. Schering bridge is one of the most widely used AC bridges.
a) True
b) False
Explanation: 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
8. Schering bridge is used for _________
a) low voltages only
b) low and high voltages
c) high voltages only
d) intermediate voltages only
Explanation: 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
9. Power factor of a Schering bridge is _________
a) p.f. = sin∅x = Zx⁄Rx
b) p.f. = cot∅x = Rx⁄Zx
c) p.f. = cos∅x = Rx⁄Zx
d) p.f. = tan∅x = Rx⁄Zx
Explanation: The power factor of the RC combination in a Schering bridge is given by the relation p.f. = cos∅x = Rx⁄Zx .
where,
Rx is the series resistance
Zx is the series impedance comprising of Rx and Cx.
10. For phase angles close to 90°, the power factor of the bridge is _________
a) p.f. = ωRx
b) p.f. = ωCx
c) p.f. = Rx Cx
d) p.f. = ωRx Cx
Explanation: When phase angle reaches 90°, reactance equals the impedance and the power factor of the bridge is calculated using the relation,
