1. What is the primary function of an ammeter?
(A) To measure voltage
(B) To measure current
(C) To measure resistance
(D) To measure power
2. What does a voltmeter measure?
(A) Electric current
(B) Electrical resistance
(C) Electric potential difference
(D) Electrical energy
3. An ammeter is always connected in:
(A) Parallel with the circuit
(B) Series with the circuit
(C) Across the load
(D) With a capacitor
4. A voltmeter is connected in:
(A) Series with the circuit
(B) Parallel with the circuit
(C) With a shunt resistor
(D) Across a switch
5. The internal resistance of an ideal ammeter is:
(A) Zero
(B) Very high
(C) Moderate
(D) Infinite
6. The internal resistance of an ideal voltmeter is:
(A) Zero
(B) Infinite
(C) Very low
(D) Equal to the load
7. The unit of electrical power is:
(A) Volt
(B) Ampere
(C) Watt
(D) Ohm
8. A wattmeter is used to measure:
(A) Electrical power
(B) Electrical energy
(C) Resistance
(D) Frequency
9. A watt-hour meter measures:
(A) Electrical energy consumption
(B) Instantaneous power
(C) Peak voltage
(D) Frequency
10. The moving coil in a PMMC instrument carries:
(A) Direct current
(B) Alternating current
(C) Pulsed voltage
(D) Magnetic flux only
11. The deflection in a PMMC instrument is proportional to:
(A) The current through the coil
(B) The square of the current
(C) The resistance
(D) The voltage drop
12. An electrodynamometer type wattmeter can measure:
(A) Both AC and DC power
(B) Only DC power
(C) Only AC power
(D) Reactive power only
13. A moving iron instrument works on the principle of:
(A) Attraction and repulsion of a soft iron piece
(B) Magnetic induction
(C) Electromagnetic damping
(D) Seebeck effect
14. In a dynamometer type wattmeter, the fixed coil carries:
(A) Current proportional to the load current
(B) Current proportional to the load voltage
(C) Both current and voltage
(D) No current
15. In an electrodynamometer wattmeter, the moving coil carries:
(A) Current proportional to the load voltage
(B) Load current directly
(C) Magnetic field flux
(D) The difference current
16. A shunt resistor is used with an ammeter to:
(A) Extend its current range
(B) Reduce its resistance
(C) Increase its sensitivity
(D) Convert it into a voltmeter
17. A multiplier resistor is used with a voltmeter to:
(A) Extend its voltage range
(B) Reduce the current
(C) Increase its sensitivity
(D) Calibrate the meter
18. The torque in a moving coil instrument is produced by:
(A) Interaction between current and magnetic field
(B) Electromagnetic induction
(C) Eddy currents
(D) Resistance change
19. The damping in a PMMC instrument is usually provided by:
(A) Eddy current damping
(B) Air friction damping
(C) Fluid damping
(D) Spring control
20. The controlling torque in an indicating instrument is provided by:
(A) Spring control or gravity control
(B) Magnetic field
(C) Damping magnet
(D) Resistance wire
21. A true RMS voltmeter measures:
(A) The effective value of AC voltage
(B) The average value of voltage
(C) The peak value of voltage
(D) The rectified voltage only
22. A digital multimeter (DMM) can measure:
(A) Voltage, current, and resistance
(B) Voltage only
(C) Power only
(D) Frequency only
23. In an AC circuit, the wattmeter reading gives:
(A) The real (active) power
(B) The apparent power
(C) The reactive power
(D) The peak power
24. The power factor of a circuit is given by:
(A) Cosine of the phase angle between voltage and current
(B) Sine of the phase angle
(C) Product of current and voltage
(D) Ratio of current to voltage
25. In a balanced three-phase system, total power is measured using:
(A) Two wattmeter method
(B) One wattmeter method
(C) Three wattmeter method only
(D) Voltmeter-ammeter method
26. If both wattmeters in a two-wattmeter method show equal readings, the power factor is:
(A) Unity
(B) Zero
(C) Lagging
(D) Leading
27. In the two-wattmeter method, one wattmeter reads negative when:
(A) The power factor is less than 0.5
(B) The power factor is unity
(C) The circuit is open
(D) Load is purely resistive
28. The Creeping error in an energy meter is caused by:
(A) Excessive friction or stray magnetic field
(B) Overload
(C) Low temperature
(D) Voltage fluctuation
29. The braking torque in an induction-type energy meter is produced by:
(A) Eddy currents
(B) Magnetic field
(C) Spring tension
(D) Electrical resistance
30. The speed of the disc in an energy meter is proportional to:
(A) Power consumed
(B) Voltage only
(C) Current only
(D) Frequency
31. A CT (Current Transformer) is used for:
(A) Measuring high current by stepping it down
(B) Measuring voltage directly
(C) Converting AC to DC
(D) Isolating power supply
32. A PT (Potential Transformer) is used for:
(A) Measuring high voltage by stepping it down
(B) Measuring current
(C) Storing energy
(D) Measuring frequency
33. The burden of an instrument transformer refers to:
(A) The load connected to its secondary winding
(B) The copper loss
(C) The voltage drop
(D) The magnetizing current
34. The ratio error in a current transformer is caused by:
(A) Magnetizing current and core losses
(B) High resistance in the secondary circuit
(C) Temperature variation
(D) Improper wiring
35. Phase angle error in instrument transformers affects:
(A) Power factor measurement accuracy
(B) Voltage reading
(C) Frequency response
(D) Insulation resistance