1. An induction wattmeter can be used for

- both DC and AC
- DC only
- AC only
- none of these

2. Wattmeter can not be designed on the principle of

- Electrostatic instrument
- Thermocouple instrument
- Moving iron instrument
- Electrodynamic instrument

3. Wattmeter is of

- PMMC type
- Dynamometer type
- Moving iron type
- Hot wire type

4. In a compensated wattmeter, the readings are corrected for errors due to

- Power consumed in current coil
- Variations in voltage and frequency
- Friction
- Power consumed in potential coil

5. Poynting-vector wattmeter works on

- Magnetic effect
- Hall effect
- Induction effect
- Heating effect

6. In two wattmeter method of measuring power, one of the wattmeters reads zero watts. The power factor of the load is

- Unity
- 0.8
- 0.5
- 0.6

7. While measuring power by two wattmeter method, the phase voltage is 3 V whereas the phase current is 0.5A. If the angle between phase current and phase voltage is 30 degrees, the total power consumed by the load will be

- 3.125 W
- 1.11 W
- 2.25 W
- 2.57 W

8. A dynamometer type of wattmeter responds to

- R.M.S value of active power
- Average value of active power
- Average value of reactive power
- R.M.S value of reactive power

9. A wattmeter is being tested under phantom-loading condition. If the wattmeter reading is 60W, the actual power consumed from the supply is

- Much higher than 60W
- 60W
- Much less than 60W
- 30W

10. In dynamometer wattmeter the compensation coil

- Has equal number of voltage coil and is connected in series with current coil
- Has equal number of turns of current coil and is connected in series with voltage coil
- Has equal number of current coil and is connected in series with current coil
- Has equal number of voltage coil and is connected in series with voltage coil

11. Which power factor results in equal reading of both wattmeter in 2 wattmeter method?

- Unity
- Half
- Zero
- None of the above

12. At which angle in two wattmeter method, one wattmeter show zero readings

- Φ = 0°
- Φ = 60°
- Φ = 90°
- Φ = 45°

13.Which of the following is not a method of resistance measurement?

- Ammeter-voltmeter method
- Post-office box method
- Ohm-meter method
- Two wattmeter method

14. Three wattmeter method of power measurement can be used to measure power in

- Both balanced and unbalanced circuits
- Balanced circuits
- None of the options
- Unbalanced circuits

15. The moving coil in a dynamometer wattmeter is connected

- In series with the fixed coil
- Across the supply
- In series with the load
- Any one of the above

16. A dynamometer type wattmeter responds to the

- Average value of active power
- Average value of reactive power
- Peak value of active power
- Peak value of reactive power

17. Two meters X and Y required 40 mA and 50 mA respectively for full-scale deflection. Then

- Both are equally sensitive
- Data are insufficient to comment
- X is more sensitive than Y
- Y is more sensitive than X

18. In the measurement of power in a balanced 3-phase circuit by two wattmeter method if the two wattmeters show equal readings. Then the power factor of the circuit is

- Zero
- Unity
- 0.8 lagging
- 0.8 leading

19. A wattmeter is marked 15A/30A, 300V/600V and its scale is marked up to 4500 watts. When the meter is connected for 30A, 600V, the point indicated 2000 watts. The actual power in the circuit is

- 2000 watts
- 4000 watts
- 6000 watts
- 8000 watts

20. The power in an unbalance 3-phases 4-wire circuit can be measured by using a _______ method.

- 4 Wattmeter
- 3 wattmeter
- 2 wattmeter
- 1 wattmeter