The resolution of 8-bit DAC is

 

ELECTRICAL & ELECTRONIC MEASUREMENTS – MODERATE LEVEL (Set-2: Q101–Q200)

Q101. The moving coil in a PMMC instrument is wound on a
A) Aluminum former
B) Wooden former
C) Steel former
D) Iron former
Answer: A

Q102. The pointer of an analog meter is made light to
A) Reduce inertia
B) Increase torque
C) Reduce accuracy
D) Increase weight
Answer: A

Q103. The temperature compensation in PMMC instruments is done using
A) Swamping resistance
B) Shunt resistor
C) Series resistor
D) Damping magnet
Answer: A

Q104. A swamping resistor is made of
A) Manganin
B) Copper
C) Aluminum
D) Iron
Answer: A

Q105. In moving iron instrument, deflection torque is proportional to
A) Square of current
B) Current
C) Voltage
D) Flux
Answer: A

Q106. In PMMC instruments, torque is proportional to
A) Current
B) Current squared
C) Flux squared
D) Voltage
Answer: A

Q107. The frequency meter measures
A) Frequency
B) Power
C) Phase angle
D) Voltage
Answer: A

Q108. In a Weston frequency meter, readings depend on
A) Ratio of inductance and capacitance
B) Supply voltage
C) Power factor
D) Resistance
Answer: A

Q109. The term “burden” of a CT refers to
A) Load connected to its secondary
B) Primary winding loss
C) Magnetizing current
D) Saturation
Answer: A

Q110. The working principle of a current transformer is
A) Mutual induction
B) Self-induction
C) Electromagnetic attraction
D) Resistance change
Answer: A

Q111. The primary of a potential transformer is connected
A) Across the supply
B) In series
C) Across load
D) Across current coil
Answer: A

Q112. The function of potential transformer is
A) Step down voltage for instruments
B) Step up current
C) Regulate frequency
D) Measure power
Answer: A

Q113. The dielectric loss is measured using
A) Schering bridge
B) Wien bridge
C) Kelvin bridge
D) Maxwell bridge
Answer: A

Q114. The insulation resistance test of cables is carried out using
A) Megger
B) Multimeter
C) Ohmmeter
D) Earth tester
Answer: A

Q115. A potentiometer works on the principle of
A) Comparison
B) Deflection
C) Induction
D) Electrostatics
Answer: A

Q116. The accuracy of a potentiometer depends on
A) Stability of supply voltage
B) Resistance of wire
C) Length of wire
D) All of the above
Answer: D

Q117. A Crompton potentiometer is used for
A) DC measurement
B) AC measurement
C) Both AC & DC
D) None
Answer: A

Q118. An AC potentiometer differs from DC potentiometer by
A) Using phase-shifting device
B) Using DC supply
C) Using moving coil
D) None
Answer: A

Q119. The standard unit of capacitance is
A) Farad
B) Henry
C) Ohm
D) Volt
Answer: A

Q120. The frequency of the AC bridge source should be
A) Same as test signal
B) Half of it
C) Double
D) Random
Answer: A

Q121. The deflection in a PMMC instrument depends on
A) Average current
B) RMS current
C) Peak current
D) None
Answer: A

Q122. The magnetic shunt is used in MI instruments to
A) Extend range
B) Dampen motion
C) Protect coil
D) None
Answer: A

Q123. The electrostatic voltmeter is used mainly for
A) High voltage measurement
B) Low current measurement
C) Frequency
D) Power
Answer: A

Q124. The inductance of a coil can be measured using
A) Maxwell bridge
B) Schering bridge
C) Kelvin bridge
D) None
Answer: A

Q125. The working principle of a fluxmeter is
A) Electromagnetic induction
B) Self-induction
C) Heating effect
D) Resistance
Answer: A

Q126. Ballistic galvanometer measures
A) Quantity of charge
B) Current
C) Power
D) Frequency
Answer: A

Q127. In a ballistic galvanometer, the damping is
A) Small
B) Large
C) Critical
D) None
Answer: A

Q128. The deflection of ballistic galvanometer is proportional to
A) Charge
B) Current
C) Time
D) Voltage
Answer: A

Q129. The term “dead zone” in instruments means
A) Range with no response
B) Overload limit
C) Zero position
D) Calibration error
Answer: A

Q130. The term “drift” refers to
A) Gradual change in readings
B) Sudden change
C) Random error
D) Parallax error
Answer: A

Q131. The accuracy is defined as
A) Closeness to true value
B) Repeatability
C) Sensitivity
D) Stability
Answer: A

Q132. The precision of instrument is
A) Degree of repeatability
B) Accuracy
C) Range
D) None
Answer: A

Q133. The instrument which can record continuously is called
A) Recording instrument
B) Indicating instrument
C) Integrating instrument
D) None
Answer: A

Q134. The deflection type instrument gives
A) Instantaneous value
B) Average value
C) RMS value
D) None
Answer: A

Q135. The mirror in a scale is used to
A) Avoid parallax error
B) Increase deflection
C) Improve torque
D) Reduce friction
Answer: A

Q136. The torque required to overcome friction in an instrument is called
A) Frictional torque
B) Control torque
C) Deflecting torque
D) Damping torque
Answer: A

Q137. The ratio error of a CT is
A) (KnIp − Is)/Is × 100
B) (Is − KnIp)/KnIp × 100
C) (KnIp/Is)
D) None
Answer: A

Q138. The standard frequency in India is
A) 50 Hz
B) 60 Hz
C) 25 Hz
D) 100 Hz
Answer: A

Q139. The type of bridge used for inductance with resistance in parallel is
A) Hay’s bridge
B) Maxwell’s bridge
C) Schering bridge
D) Wien bridge
Answer: A

Q140. The oscilloscope time base produces
A) Sawtooth waveform
B) Square waveform
C) Triangular waveform
D) Sine waveform
Answer: A

Q141. A dual trace CRO can display
A) Two waveforms simultaneously
B) One waveform
C) Voltage only
D) None
Answer: A

Q142. In a CRO, the horizontal plates deflect beam
A) Vertically
B) Horizontally
C) Circularly
D) None
Answer: B

Q143. In a CRO, intensity control changes
A) Brightness
B) Focus
C) Deflection
D) Time base
Answer: A

Q144. The vertical amplifier in CRO amplifies
A) Input signal
B) Sweep voltage
C) Trigger signal
D) All
Answer: A

Q145. The trigger circuit in CRO ensures
A) Stable display
B) Brightness
C) Amplification
D) Magnification
Answer: A

Q146. The sweep generator produces
A) Sawtooth voltage
B) Rectangular pulse
C) Sine wave
D) Step voltage
Answer: A

Q147. The electron gun in CRO produces
A) Focused electron beam
B) Magnetic field
C) Electrostatic field
D) None
Answer: A

Q148. The term “spot” on CRO screen is formed by
A) Electron beam striking phosphor
B) Magnetic field
C) Light reflection
D) Voltage
Answer: A

Q149. The horizontal sensitivity is expressed in
A) Time/div
B) Volt/div
C) Amp/div
D) None
Answer: A

Q150. Lissajous figures in CRO are used for
A) Phase and frequency measurement
B) Current measurement
C) Power measurement
D) Resistance measurement
Answer: A

Q151. The sensitivity of CRO depends on
A) Deflection factor
B) Accelerating voltage
C) Plate voltage
D) All
Answer: D

Q152. The bandwidth of an oscilloscope determines
A) Maximum measurable frequency
B) Accuracy
C) Range
D) Gain
Answer: A

Q153. A frequency counter counts
A) Pulses per second
B) Cycles per minute
C) Voltage
D) Resistance
Answer: A

Q154. The resolution of digital frequency meter increases with
A) Gate time
B) Supply voltage
C) Input amplitude
D) Temperature
Answer: A

Q155. A function generator can produce
A) Sine, square, and triangular waves
B) Only sine wave
C) Only square wave
D) None
Answer: A

Q156. The RMS value of a symmetrical square wave equals
A) Its peak value
B) 0.707 × peak
C) 0.5 × peak
D) 1.414 × peak
Answer: A

Q157. The form factor of a square wave is
A) 1
B) 1.11
C) 1.414
D) 0.707
Answer: A

Q158. The true RMS voltmeter measures
A) Heating value of waveform
B) Average value
C) Peak value
D) None
Answer: A

Q159. A rectifier-type voltmeter reads
A) RMS of sine wave only
B) Average of rectified current
C) Peak value
D) None
Answer: B

Q160. The electrostatic instrument is based on
A) Force between charged plates
B) Magnetic field
C) Current flow
D) None
Answer: A

Q161. The main error in electrostatic voltmeter is due to
A) Stray capacitance
B) Temperature
C) Resistance
D) Magnetic field
Answer: A

Q162. The Wheatstone bridge is used for
A) Medium resistance measurement
B) Low resistance
C) High resistance
D) Capacitance
Answer: A

Q163. In a Wheatstone bridge, for balance
A) No current flows through galvanometer
B) Voltage zero across arms
C) Current zero through ratio arms
D) None
Answer: A

Q164. For measurement of high resistance, use
A) Megger
B) Ohmmeter
C) Kelvin bridge
D) None
Answer: A

Q165. The megger works on
A) Electromagnetic induction
B) Electromagnetic attraction
C) Electrostatic induction
D) Both A & B
Answer: D

Q166. The loss factor of dielectric =
A) tan δ
B) cot δ
C) sin δ
D) cos δ
Answer: A

Q167. The instrument used to measure dielectric loss is
A) Schering bridge
B) Maxwell bridge
C) Wien bridge
D) Kelvin bridge
Answer: A

Q168. The capacitance is inversely proportional to
A) Plate separation
B) Area
C) Dielectric constant
D) None
Answer: A

Q169. The inductance depends on
A) Number of turns
B) Permeability
C) Area of coil
D) All
Answer: D

Q170. The standard capacitor is used for calibration of
A) AC bridges
B) DC bridges
C) Voltmeters
D) None
Answer: A

Q171. The bridge balance depends on
A) Phase angle equality
B) Magnitude equality
C) Both
D) None
Answer: C

Q172. The RMS value of current is measured by
A) Dynamometer type
B) PMMC
C) Hot-wire
D) None
Answer: C

Q173. The damping provided in dynamometer type instrument is
A) Air friction
B) Eddy current
C) Fluid
D) Magnetic
Answer: A

Q174. The instrument used for reactive power measurement is
A) Dynamometer wattmeter
B) Induction type wattmeter
C) Electrostatic voltmeter
D) None
Answer: A

Q175. A vector voltmeter measures
A) Phase and magnitude
B) Frequency
C) Resistance
D) None
Answer: A

Q176. The maximum torque occurs in MI instrument at
A) 45°
B) 90°
C) 30°
D) 60°
Answer: A

Q177. In moving-iron type, scale is crowded
A) Near zero
B) Near full-scale
C) Uniform
D) None
Answer: A

Q178. The PMMC instruments cannot be used for AC because
A) Torque reverses every half cycle
B) Heating occurs
C) Coil burns
D) Magnet loses strength
Answer: A

Q179. Induction type energy meter is not used for DC because
A) Works on alternating flux
B) Magnetic field is steady
C) Eddy current loss
D) None
Answer: A

Q180. The braking torque of induction meter is proportional to
A) Speed
B) Flux
C) Load current
D) None
Answer: A

Q181. In energy meter, creeping may be caused by
A) Over-voltage
B) Over-fluxing
C) Excess friction
D) Vibrations
Answer: D

Q182. Creep compensation holes are placed
A) Opposite to each other
B) Randomly
C) On periphery
D) Center
Answer: A

Q183. The shunt resistance in ammeter is made of
A) Manganin
B) Copper
C) Iron
D) Nickel
Answer: A

Q184. The multiplier in voltmeter is connected
A) In series
B) In parallel
C) Across load
D) None
Answer: A

Q185. The power loss in shunt resistance should be
A) Minimum
B) Maximum
C) Zero
D) Moderate
Answer: A

Q186. A digital storage oscilloscope stores signal in
A) Memory
B) CRT
C) Capacitor
D) Coil
Answer: A

Q187. The sampling theorem states sampling frequency must be
A) ≥ twice signal frequency
B) Equal
C) Half
D) Any value
Answer: A

Q188. The main advantage of DSO is
A) Can capture transient signals
B) Low cost
C) Analog accuracy
D) None
Answer: A

Q189. The voltmeter loading error is maximum when
A) Source resistance is high
B) Source resistance is low
C) Load is small
D) None
Answer: A

Q190. A digital voltmeter converts
A) Analog to digital
B) Digital to analog
C) AC to DC
D) DC to AC
Answer: A

Q191. The main component in digital voltmeter is
A) ADC
B) DAC
C) Filter
D) Oscillator
Answer: A

Q192. The accuracy of dual-slope ADC depends on
A) Integrator time constant
B) Clock frequency
C) Reference voltage
D) All
Answer: D

Q193. The number of bits in ADC determines
A) Resolution
B) Speed
C) Range
D) None
Answer: A

Q194. The SAR ADC is preferred for
A) Medium speed, high accuracy
B) High speed
C) Low speed
D) None
Answer: A

Q195. The sample-and-hold circuit uses
A) Capacitor to store voltage
B) Resistor
C) Inductor
D) Transistor only
Answer: A

Q196. The error in ADC conversion due to step size is
A) Quantization error
B) Offset error
C) Gain error
D) None
Answer: A

Q197. The DAC converts
A) Digital to analog
B) Analog to digital
C) Voltage to current
D) None
Answer: A

Q198. The resolution of 8-bit DAC is
A) 1/256
B) 1/128
C) 1/512
D) 1/1024
Answer: A

Q199. The accuracy of DAC depends on
A) Resistor tolerance
B) Reference voltage
C) Linearity
D) All
Answer: D