Electrical measurements MCQ Quiz Hub

1. In A.C. circuits, power is measured using ____
voltmeter
ammeter
ohmmeter
wattmeter

2. A wattmeter consists of a current coil and a potential coil.
True
False
all of the above
None of the mentioned

3. A dynamometer type wattmeter consists of ________
only potential coil
potential and current coils
only current coil
no coils

4. Controlling torque is provided by gold springs.
True
False
all of the above
None of the mentioned

5. In a Dynamometer type wattmeter, the fixed coil is split into ________
4
3
2
1

6. When a current carrying coil is placed in the magnetic field?
no force is exerted
voltage is produced
power is generated
a force is exerted

7. Pressure coil of a wattmeter _____
has capacitance and inductance
has inductance and resistance
has resistance and capacitance
has only inductance

8. Wattmeter reading is not affected by temperature.
True
False
all of the above
None of the mentioned

9. Dynamometer type wattmeter has ______
strong magnetic field
intermediate magnetic field
weak magnetic field
no magnetic field

10. Wattmeter reading has errors induced by _____
resistance
self-capacitance
self-inductance
mutual inductance

11. Current in a pressure coil of the Dynamometer type wattmeter ________
lags the applied voltage
leads the applied voltage
is in phase with the applied voltage
there is a phase difference of 90 degrees

12. Wattmeters are compensated for errors due to inductance by _________
using a series capacitor
using a parallel capacitor
using a series resistance
using a parallel resistance

13. Eddy currents are induced in solid metal parts within the thickness of the conductor.
True
False
all of the above
None of the mentioned

14. What is the effect of frequency on the torque of a moving system?
torque is half of the frequency
torque is twice the frequency
torque is thrice the frequency
torque is four times the frequency

15. In an ordinary dynamometer, the deflecting torque is ____
small
medium
large
very large

16. Errors are introduced by _____
capacitance
inductance
resistance
impedance

17. Power coil has a low value of ________
inductance
capacitance
resistance
impedance

18. Resistance of pressure coil in a low power factor dynamometer type wattmeter is _____
once time
three times
hundred times
ten times

19. Low power factor wattmeters are designed to ________
have a low torque
have a high torque
have a medium torque
have no torque

20. Power loss in the current coil is ______
less
more
intermediate
very less

21. Pressure coil has no error.
True
False
all of the above
None of the mentioned

22. Error in a pressure coil can be compensated.
True
False
all of the above
None of the mentioned

23. Induction type instruments are used for ______
A.C. measurements
D.C. measurements
Resistance measurements
Voltage measurements

24. Driving system in an induction type single phase energy meter consists of ________
one magnet
two electromagnets
five electromagnets
ten magnets

25. Series electromagnet consists of _________
L shaped laminations
T shaped laminations
U shaped laminations
Y shaped laminations

26. Shunt magnet consists of _______
N shaped laminations
E shaped laminations
S shaped laminations
M shaped laminations

27. Shunt magnet has _____
large turns of wire
small turns of wire
medium turns of wire
no turns or wires

28. Moving system of the induction type single phase energy meter has _____
heavy aluminium disc
light aluminium disc
medium aluminium disc
no aluminium disc

29. Braking system consists of _____
bar magnet
temporary magnet
permanent magnet
super magnet

30. What is the effect of eddy currents in the aluminium disc?
varies by a factor of twice the disc length
independent of the disc speed
varies by a factor of four times the disc size
proportional to the disc speed

31. An energy meter produces a flux of ∅ when connected to a supply V.
True
False
all of the above
None of the mentioned

32. The energy meter always measures the load energy correctly.
True
False
all of the above
None of the mentioned

33. Obtaining correct reading from the energy meter requires ______
low resistance and iron losses
high resistance and iron losses
high resistance and low iron losses
low resistance and high iron losses

34. Phase angle can be made 90 degrees using ____
lead circuit
lag circuit
special design
transformer

35. Shading coil consists of many thick turns.
True
False
all of the above
None of the mentioned

36. Copper shading bands are _________
placed as resistance
placed as wire
placed outside the central limb
placed around central limb

37. As copper shading bands move up _____
more flux is induced
less flux is induced
intermediate flux is induced
no flux is induced

38. Shunt flux is made to lag the applied voltage using ________
lead circuit
lag adjustment
lead-lag circuit
transformer

39. At overloads, magnetic shunt ________
aids the series flux
diverts series flux
maintains zero flux
disables the shunt flux

40. Energy meter reads correctly when the _______
torque is small
torque is large
torque is medium
torque is zero

41. Small torque for energy meter is provided ________
by a supply
by a shading loop
by unshaded loop
by a transformer

42. Driving torque is small and is adjustable.
True
False
all of the above
None of the mentioned

43. Friction torque is eliminated by ________
using lubricating oil
by suspending the components in air
by adjusting the position of limb
by using steel alloy components

44. Frictional errors are dominant in an energy meter.
True
False
all of the above
None of the mentioned

45. At full load, disc ______
partially revolves and then stops
continuously revolves
does not revolve at all
revolves in an alternating fashion

46. Self braking torque is _____
proportional to cube of load current
proportional to load current
proportional to square of load current
proportional to reciprocal of load current

47. Self braking action is minimised by _______
maintaining high speed for disc
maintaining medium speed for disc
keeping the disc at rest
maintaining low speed for disc

48. Overload compensating devices is ______
in the form of a magnetic shunt
in the form of a series magnet
in the form of a transformer
in the form of a supply

49. Magnitude of flux in an energy meter varies _______
due to abnormal currents and voltages
due to high resistance and inductance values
due to changes in the transformer turns
due to the induced e.m.f in the windings

50. Phase angles in an energy meter cannot be incorrect.
True
False
all of the above
None of the mentioned