Q101. Which instrument has uniform scale?
A) PMMC
B) Moving Iron
C) Induction type
D) Electrostatic
Ans: A
Q102. Which error is eliminated in Kelvin double bridge?
A) Temperature error
B) Lead and contact resistance error
C) Parallax error
D) Hysteresis error
Ans: B
Q103. The unit of dielectric loss angle is:
A) Degree or radian
B) Watt
C) Henry
D) Farad
Ans: A
Q104. Which bridge is used for Q-factor measurement of inductors?
A) Maxwell’s bridge
B) Hay’s bridge
C) Wien bridge
D) Schering bridge
Ans: B
Q105. The most accurate method of resistance measurement is:
A) Wheatstone bridge
B) Potentiometer
C) Kelvin bridge
D) Voltmeter–ammeter method
Ans: C
Q106. Induction type instruments can only be used for:
A) AC measurements
B) DC measurements
C) Both AC and DC
D) Transient measurements
Ans: A
Q107. A fluxmeter is a special type of:
A) Ammeter
B) Voltmeter
C) Galvanometer
D) Energy meter
Ans: C
Q108. A ballistic galvanometer is mainly used for:
A) Steady current
B) Charge measurements
C) Power measurements
D) Frequency measurement
Ans: B
Q109. The control torque in gravity controlled instruments is proportional to:
A) sinθ
B) cosθ
C) tanθ
D) θ
Ans: B
Q110. Which instrument measures RMS value irrespective of waveform?
A) MI instrument
B) Hot-wire instrument
C) PMMC instrument
D) Electrostatic voltmeter
Ans: B
Q111. A synchroscope shows:
A) Synchronism between two alternators
B) Voltage
C) Frequency only
D) Current only
Ans: A
Q112. Which factor affects creeping error in energy meters?
A) Overvoltage
B) Vibration
C) Overcompensation of friction
D) All of the above
Ans: D
Q113. The essential feature of a potentiometer is:
A) Very high resistance
B) Uniform potential drop per unit length
C) Small size
D) Zero resistance
Ans: B
Q114. Volt-ratio box is used with potentiometer to:
A) Extend voltage range
B) Increase accuracy
C) Measure resistance
D) Reduce current
Ans: A
Q115. The standard used in a Kelvin double bridge is:
A) Capacitor
B) Low resistance standard
C) High resistance
D) Frequency
Ans: B
Q116. An instrument which measures without consuming power from the circuit is:
A) Electrostatic voltmeter
B) PMMC voltmeter
C) Hot-wire instrument
D) Wattmeter
Ans: A
Q117. The two wattmeter method of power measurement is applicable to:
A) Single-phase only
B) Balanced three-phase only
C) Balanced and unbalanced three-phase
D) DC circuits only
Ans: C
Q118. At unity power factor, the readings of two wattmeters in a 3-phase system are:
A) Equal and positive
B) Equal and negative
C) Equal and opposite
D) Zero
Ans: A
Q119. A synchroscope pointer rotating slowly clockwise indicates:
A) Incoming machine frequency is lower
B) Incoming machine frequency is higher
C) Machines are in phase
D) Both frequencies are equal
Ans: B
Q120. Loss of charge method is used for measurement of:
A) Resistance
B) Capacitance
C) Inductance
D) Power
Ans: A
Q121. Which instrument uses an attraction and repulsion vane?
A) PMMC
B) MI instrument
C) Electrodynamometer
D) Hot-wire instrument
Ans: B
Q122. The deflecting torque of MI instrument is proportional to:
A) I
B) I²
C) V
D) V²
Ans: B
Q123. The swamping resistance in voltmeter is made of:
A) Copper
B) Manganin
C) Aluminum
D) Iron
Ans: B
Q124. Damping torque is NOT provided by:
A) Eddy currents
B) Fluid friction
C) Air friction
D) Spring
Ans: D
Q125. The main source of error in electrodynamometer type wattmeter is:
A) Pressure coil inductance
B) Spring weakness
C) Scale error
D) Damping
Ans: A
Q126. Which method gives most accurate frequency?
A) Synchroscope
B) Frequency meter
C) CRO Lissajous method
D) Tachometer
Ans: C
Q127. A vibration galvanometer is used to measure:
A) DC
B) AC frequency
C) Current
D) Resistance
Ans: B
Q128. A digital multimeter (DMM) can measure:
A) V, I, R
B) Continuity
C) Capacitance/diode test (in some models)
D) All of the above
Ans: D
Q129. Which has the least power consumption?
A) Digital instruments
B) Analog instruments
C) MI instruments
D) PMMC instruments
Ans: A
Q130. In wattmeter, pressure coil is made highly:
A) Resistive
B) Inductive
C) Capacitive
D) Reactive
Ans: A
Q131. Range of CRO vertical deflection depends on:
A) Amplifier gain
B) Time base
C) Sweep circuit
D) Triggering
Ans: A
Q132. For AC, an integrating instrument is:
A) Energy meter
B) Wattmeter
C) Ammeter
D) Voltmeter
Ans: A
Q133. The accuracy of electrodynamometer instruments is:
A) ±0.1%
B) ±0.5%
C) ±1%
D) ±5%
Ans: B
Q134. A null detector in Wheatstone bridge is generally:
A) Ammeter
B) Galvanometer
C) Voltmeter
D) Wattmeter
Ans: B
Q135. Thermocouple instruments measure:
A) Current only
B) Voltage only
C) RMS value of AC
D) Frequency
Ans: C
Q136. In Schering bridge, loss angle is obtained from:
A) Resistance arm
B) Capacitance arm
C) Ratio arms
D) Both A & C
Ans: D
Q137. Which error is minimized by using high resistance in potentiometer circuit?
A) Loading error
B) Temperature error
C) Hysteresis error
D) Observational error
Ans: A
Q138. The accuracy of an energy meter is expressed as:
A) % error
B) % creep
C) % deviation
D) % deflection
Ans: A
Q139. Which damping is most commonly used in MI instrument?
A) Eddy current
B) Air friction
C) Fluid friction
D) Spring damping
Ans: B
Q140. A 1-phase power factor meter is of:
A) Induction type
B) Dynamometer type
C) MI type
D) Electrostatic type
Ans: B
Q141. The principle of operation of Weston frequency meter is:
A) Resonance
B) Magnetic deflection
C) Induction
D) Electrostatic
Ans: A
Q142. A high voltage measurement uses:
A) Electrostatic voltmeter
B) PMMC
C) MI
D) Potentiometer
Ans: A
Q143. In Maxwell’s bridge, unknown parameter is:
A) Resistance
B) Inductance
C) Capacitance
D) Frequency
Ans: B
Q144. CRO can be used to measure:
A) Phase difference
B) Frequency
C) Voltage waveform
D) All of the above
Ans: D
Q145. Ohmmeter is based on:
A) Series type circuit
B) Shunt type circuit
C) Both A & B
D) Potentiometer
Ans: C
Q146. The sensitivity of a potentiometer is increased by:
A) Increasing length of wire
B) Decreasing length of wire
C) Using thick wire
D) None
Ans: A
Q147. The main error in digital instruments is due to:
A) Quantization
B) Parallax
C) Hysteresis
D) Friction
Ans: A
Q148. An analog energy meter registers energy in:
A) Joules
B) Watt-seconds
C) kWh
D) kVA
Ans: C
Q149. Which bridge uses a vibration galvanometer?
A) Maxwell bridge
B) Schering bridge
C) AC bridges
D) Wien’s bridge
Ans: C
Q150. The ratio of maximum scale reading to least count is called:
A) Accuracy
B) Precision
C) Resolution
D) Range/Resolution ratio
Ans: C
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