1. 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
Explanation: In a series RC circuit, δ refers to the angle between the series combination of Rx, Cx and the voltage across the capacitance Cx. δ is also known as the loss angle.
2. 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
Explanation: The expression for the loss angle can be computed as the ratio of the tangent of the voltage drop across resistance Rx to the voltage drop across the capacitance Cx.
3. Quality factor is given by which of the following expression?
a) Q = 1⁄R
b) Q = R
c) Q = X⁄R
d) Q = XR
Explanation:The quality factor the Schering bridge circuit is defined as Q = X⁄R.
where, X = 1⁄wC is the capacitive impedance.
4. Dissipation factor is the reciprocal of quality factor.
a) True
b) False
Explanation: 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.
5. 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
Explanation: 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%.
6. A Schering bridge can be used for the ______________
a) measuring voltages
b) measuring currents
c) testing capacitors
d) protecting the circuit from temperature rises
Explanation: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
7. A Schering bridge can be used for capacitance measurements at low voltages.
a) True
b) False
Explanation: When a Schering bridge is used for the measurement of small capacitances at low voltages, it comprises of errors. In order to avoid this a high voltage Schering bridge is used.
8. How is the high voltage obtained?
a) by using a step up transformer
b) by using a high voltage source
c) by using a step down transformer
d) by using a high current source
Explanation: High voltage supply for a Schering bridge is obtained by making use of a step up transformer. The frequency for the high voltage supply used in a Schering bridge is 50 Hz.
9. The detector used in a high voltage Schering bridge is _________
a) tunable circuit
b) e.m.f source
c) vibration galvanometer
d) headphone
Explanation: A high voltage Schering bridge is used for the measurement of low capacitance values at high voltages. A vibration galvanometer is used as a detector in a high voltage Schering bridge.
10. Detector is very sensitive in a high voltage Schering bridge.
a) True
b) False
Explanation: In a high voltage Schering bridge the ratio arms have high impedance values. As a result, a very small current is drawn by the ratio arms. Hence the detector must be very sensitive in a high voltage Schering bridge.