# Multiple Choice Question (MCQ) of Measurements page-10

91. The wattmeter

a) Has voltage and current coils to measure the real power
b) Has three connections two of which are used at a time
c) Measures apparent power because the current is same in the voltage and current coils
d) Can measure d.c. power but not 60 cps a.c. power

Ans: (a)

92. Which of the following statement is true ?

a) The hysteresis loss can be determined from the area of B-H curve
b) Eddy current loss is determined from the area of B-H curve
c) Hysteresis and eddy current losses can be determined from the area of the B-H loop
d) None of the above losses is determined from the B-M loop

Ans: (a)

93. The damping of the ballistic galvanometer is kept very small

a) To make the system oscillating
b) In order to get first deflection large
c) In order to get first deflection small
d) To make the system critically damped

Ans: (b)

94. The grosset fluxmeter is special type of ballistic galvanometer in which

a) Controlling torque is small and damping is heavy
b) Controlling torque and damping are large
c) Controlling torque is large but damping is small
d) Controlling torque and damping are small

Ans: (a)

95. Ballistic galvanometer can be used to measure the current and flux both.

a) True
b) False

Ans: (a)

96. Which of the following frequency meter is suitable to measure radio frequency ?

a) Electrical resonance frequency meter
b) Weston frequency meter
c) Heterodyne frequency meter
d) Either (b) or (c)

Ans: (c)

97. Enumerate the advantages of moving iron power factor meter over the dynamometer type power factor meter

a) Large working forces
b) A scale which extends to 360°
c) The absence of ligaments to lead in current to moving coils, all coils in the moving iron types being fixed

Ans: ()

98. Enumerate the sources of errors in the moving coil instruments

a) Weakening of permanent magnets due to ageing and temperature effect
b) Weakening of spring due to ageing and temperature effect
c) Change of resistance of moving coil with temperature

Ans: ()

99. Enumerate the errors in moving iron instruments with both A.C. and D.C.

a) Hysteresis error
b) Stray magnetic fields
c) Temperature error

Ans: ()

100. Enumerate the errors in moving iron ammeter with a.c. only

a) Frequency errors
b) Reactance of instrument coil
c) Eddy currents

Ans: ()