Questions
1
Hysteresis of an instrument means:
Answer: The change in the same reading when input is first increased and then decreased
2
In which part of the scale does the pointer indicate more accurately
Answer: In about middle of the scale
3
A 150 V moving iron voltmeter of accuracy class 1.0 reads 75 V when used in a circuit under a standard conditions. The maximum possible percentage error in the reading is:
Answer: 2.0
4
The moving iron voltmeters are likely:
Answer: To indicate lower value of ac than on dc
5
Hay’s Bridge is suitable for the measurement of:
Answer: Inductances with Q>10
6
The ballistic galvanometer is usually lightly damped so that:
Answer: Amplitude of the first swing is large
9
Moving iron and PMMC instruments can be distinguished from each other by looking at:
Answer: Scale
10
The deflection of hot-wire instrument depends on:
Answer: RMS value of the alternating current
11
The damping torque must operate only when the moving system of the indicating instrument is:
Answer: Actually moving
12
Air friction damping is used in the instruments which is:
Answer: Moving iron
17
Which of the following instruments have least torque/weight ratio:
Answer: Dynamometer type
18
The instrument having its deflection depends upon average value is:
Answer: Rectifier type
19
Which of the following instruments can be used for full scale deflection of 300o:
Answer: Induction type
