Electromagnetic Instrumentation MCQ's
1) When
condition R1/R2 = R3/R4 is
satisfied, current in galvanometer of Wheatstone bridge is
(a)
(b) 0
(c) min
(d) max
2)
Bridge circuits are used for the measurement of
(a) Resistance
(b) Inductance
(c) Capacitance
(d)All of these
(3) Low resistance is the resistance
of the order of
A. 1 ohm and less than 1 ohm
B. 1 ohm to 1 mega ohm
C. More
than one ohm
D. None of
these
(4) The accuracy in a bridge
measurement depends on
A.
Sensitivity of detector
B.
Applied voltage
C.
Accuracy of indicator
D. Both (a) and (b)
(5) A null type of bridge with dc
excitation is commonly known as
A. Wheatstone bridge
B. Anderson bridge
C. Wien
bridge
D.
Schering bridge
(6) In Wheatstone bridge method, the
instrument used as null detector is
A. Ammeter
B. Voltmeter
C. Galvanometer
D. All of these
(7) The sensitivity of Wheatstone
bridge is defined as ratio of
A. Deflection of the galvanometer to the unit
fractional change in the value of unknown
resistance
B. Square
of the deflection of the galvanometer to the unit fractional change in the
value of
unknown resistance
C.
Deflection of the galvanometer to the twice of the unit fractional change in
the value of
unknown resistance
D. Unit
fractional change in the value of unknown resistance to the deflection of the
galvanometer
(8) Which of the following device is
used with 4 terminal resistors?
a)
Wheatstone bridge
b) Hay bridge
c) Wien bridge
d) Kelvin bridge
(9) Why 4 terminal resistors are used?
a) For
protection
b) To overcome parasitic resistances
c) To
increase current flow
d) None of
mentioned
(10) Accuracy in a bridge measurement depends on
a)
Sensitivity of detector
b)
Applied voltage
c) Both Sensitivity and applied voltage
d)
Accuracy of indicator
(11) The vibration galvanometers are
sensitive to power for frequency range of
A. 200 Hz and below
B. 200 Hz to about 4 kHz
C. 4 kHz
and above
D. Any
frequency
(12) The vibration galvanometer used as detector, it responds
A. Only to the fundamental frequency
B. Only to the harmonics frequency
C. Both
(a) and (b)
D.
Does not respond to any frequency
(13) The Ac Bridge used for the
measurement of inductance is/are
A.
Maxwell’s inductance bridge
B.
Hay’s bridge
C.
Anderson’s bridge, Owen’s bridge
D. All of these
(14) In Maxwell’s Inductance-Capacitance bridge, the frequency ω
A. Is directly proportional to the inductance in the balanced equation
B. Is inversely proportional to the capacitance in the balanced equation
C. Is directly proportional to the product of inductance and capacitance
D. Does not appear in the balanced equations
(15) The Maxwell’s Inductance-Capacitance bridge is not suitable for the measurement inductance of coil if the Q factor is
A. Less
than
B. Between 1 to 10
C. More than 10
D. Both (a)
and (c)
(16) The Q meter works on the principle of
A. Series resonance
B. Parallel resonance
C. Both (a) and (b)
D. Neither
series resonance nor parallel resonance
(17) Schering Bridge is used to measure
A. Dielectric Loss
B. Capacitance and its pf
C. Both
(18) Hay bridge is suitable for Q greater than
A. 10
(19) Bridge Used to determine Frequency
A. Wein Bridge
B. Maxwell Bridge
(20) Crompton potentiometer has
A. 14 coils and a slide wire all having the
same resistance
B.14 coils
and a slide wire but the resistance of slide wire is half that of each coil
C.14 coils
each of different resistance
D.14 coils
out of which 7 coils have resistance which is twice that of remaining 7 coils
(21) The volt ratio box is basically a
A.
Potential divider
B. Current transformer
C. A high resistance voltmeter
D. Either (a) or (c)
(22) In an Anderson bridge the unknown inductance is measured in terms of
A. known inductance and resistance
B. known
inductance
C.
known capacitance and resistance
D. known capacitance
(23) Wagner earthing device is used to eliminate error due to
A. electromagnetic
coupling
B. electrostatic coupling
C.both
electrostatic and electromagnetic coupling
D.
either (a) or (b)
(24) Which wave has the least value of form factor?
(A) Square wave.
(B) Rectangular wave
(C) Sine wave
(D) Triangular wave.
(25) A Weston frequency meter is
(A) moving
coil instrument.
(B) moving iron instrument
(C)
dynamometer instrument
(D) none of the
above.
(26) A Weston synchronoscope is a
(A) moving
coil instrument
(B) moving iron
instrument.
(C) dynamometer instrument
(D) none of the above.
(27) In a low power factor wattmeter the pressure coil is connected
(A) to the
supply side of the current coil
(B) to the load side of the current coil
(C) in any
of the two meters at connection
(D)
none of the above.
(28) In a low power factor wattmeter the compensating coil is connected
(A) in
series with current coil
(B) in
parallel with current coil
(C) in series with pressure coil
(D) in parallel with pressure coil.
(29) Which of the following damping is mostly provided in electrical instruments?
(A) fluid
friction
(B) spring
(C)
eddy current.
(D) all of
the above.
(30) A Dynamometer type wattmeter responds to the
(A) Average value of the active power.
(B) Average value of the
reactive power
(C) Peak
value of the active power
(D)
Peak value of the reactive power.
(31) In a meggar controlling torque is provided by
(A)
spring
(B) gravity
(C)
coil
(D) eddy current.
(32) Campbell’s bridge method is used to measure
(A) Copper
loss.
(B) iron loss
(C) Both iron and copper loss
(D)
None of the above.
(33) Which of the following ammeter is preferred to measure high frequency currents?
(A) moving iron.
(B) moving coil.
(C) dynamo meter.
D) thermocouple.
Comments
Post a Comment