Multiple Choice Questions in Measurements- 1

Multiple Choice Questions in Measurements

1.       When reading is taken at half scale in the instrument, the error  is

a)      Exactly equal to half of full-scale error

b)      Equal to full-scale error

c)       Less than full-scale error

d)      More than full-scale error

2.       Torque/weight ratio of an instrument indicates

a)      Selectivity

b)      Accuracy

c)       Fidelity

d)      Sensitivity

3.       The errors introduced by the instrument fall in which category?

a)      Systematic errors

b)      Random errors

c)       Gross errors

d)      Environmental errors

4.       A Wheatstone bridge requires a change of 6 Ω in the unknown arm of the bridge to produce a change in deflection of 3 mm of the galvanometer. The sensitivity of the instrument is

a)      0.5%

b)      2%

c)       0.5 mm/Ω

d)      2.0 Ω/mm

5.       Identify which one is not a fundamental unit in SI system

a)      Ampere

b)      Kelvin

c)       Metre

d)      Joule

6.       Due to which one of the following reasons bearings of PMMC instrument are made up of jewel?

a)      To avoid wear and tear of the moving system

b)      To provide a small support

c)       It can be easily replaced

d)      To make the system robust

7.       Normally, swamping resistance which is connected in series with the working coil of galvanometer is made of

a)      Constantan

b)      Eureka

c)       Manganin

d)      Nichrome

8.       The response of a galvanometer is independent of its

a)      Controlling torque

b)      Number of turns

c)       Circuit resistance

d)      None of these

9.       Why is damping of ballistic galvanometer kept small?

a)      To get minimum overshoot

b)      To make the system critically damped

c)       To make the system oscillatory

d)      To get first deflection large

10.   If an instrument has square law response, it can be used for the measurement of

a)      Ac only

b)      Both ac and dc

c)       Dc only

d)      None of the above

11.   Spiral springs are used in instruments to

a)      Provide controlling torque

b)      Provide damping torque

c)       Lead the current to the moving coil as well as to provide the controlling torque

d)      Provide linear deflection

12.   A spring-controlled moving iron voltmeter draws a current of 1 mA for full-scale value of 100 V. if it draws a current of 0.5 mA, the meter reading is

a)      25V

b)      50V

c)       100V

d)      200V

13.   One of the control springs of a permanent magnet moving coil ammeter is broken. If connected in a circuit, the meter would read

a)      Zero

b)      Half the correct value of the current

c)       Twice the correct value of the current

d)      An indefinite figure

14.   A moving coil of a meter has 100 turns, and a length and depth of 10 mm and 20 mm respectively. It is positioned in a uniform radial flux density of 200 mT. the coil carries a current of 50 mA. The torque on the coil is

a)      200µNm

b)      100 µNm

c)       2 µNm

d)      1 µNm

15.   Rectifier moving coil responds to

a)      Peak value  irrespective of the nature of the wave form

b)      Average value for all wave forms

c)       Rms value for all wave forms

d)      Rms value for symmetrical square wave forms

16.   A galvanometer with a full scale current of 10 mA has a resistance of 1000Ω. The multiplying power (the ratio of measured current to galvanometer current) of a 100Ω shunt with this galvanometer is

a)      110

b)      100

c)       11

d)      10

17.   The moving coil in a dynamometer wattmeter is connected

a)      In series with the fixed coil

b)      Across the supply

c)       In series with the load

d)      Across the load

18.   Due to inductance in the pressure coil the dynamometer wattmeter reads

a)      Lower on lagging power factor and higher on leading power factor than the actual value

b)       higher on lagging power factor and lower on leading power factor than the actual value

c)       Actual value

d)      Always reads lower than the actual value

19.   If the power factor is below 0.5 in two wattmeter method of power measurement

a)      One of the wattmeter will give negative deflection

b)      Both the wattmeters will give negative deflection

c)       Both the wattmeters will give positive deflection

d)      Both the wattmeters will not give any deflection

20.   The voltage coil of a single phase house energy meter

a)      Is highly resistive

b)      Is highly inductive

c)       Is highly capacitive

d)      Has a phase angle equal to load power factor angle

21.   If an induction type energy meter runs fast, it can be slowed down by

a)      Lag adjustment

b)      Light load adjustment

c)       Adjusting the position of braking magnet and moving it closer to the center of the disc

d)      Adjusting the position of braking magnet and moving it away from  the center of the disc

22.   Which one of the following frequency meter is suitable for measuring radio frequency?

a)      Vibrating reed frequency meter

b)      Weston frequency meter

c)       Electrical resonance frequency meter

d)      Heterodyne frequency meter

23.   Which one of the following instrument is used for standardization of drysdale ac potentiometer?

a)      Rectifier type ammeter

b)      PMMC ammeter

c)       Precision type electrodynamometer

d)      Thermocouple ammeter

24.   The resistance of shunt for a precision grade ammeter can be best measured by

a)      De sauty bridge

b)      Schering bridge

c)       Max well bridge

d)      Kelvin double bridge

25.   In an Anderson bridge, the unknown inductance is measured in

a)      Resistance

b)      Capacitance

c)       Inductance and resistance

d)      Resistance and capacitance

26.   Hay’s bridge is suitable for the measurement of which one of the following?

a)      Inductance with Q<10

b)      Inductance with Q>10

c)       Capacitance with high dissipating factors

d)      Capacitance with low dissipating factors

27.   Inductance is measured by which one of the following?

a)      Wien bridge

b)      Schering bridge

c)       Maxwell bridge

d)      Owen bridge

28.   Which one of the following bridge is used for measurement of dielectric loss and power factor of a capacitor?

a)      Maxwell’s bridge

b)      Anderson bridge

c)       De sauty’s bridge

d)      Schering bridge

29.   Wagners earth devices in an ac bridge circuits are used for

a)      Shielding all the bridge elements from external magnetic field

b)      Eliminating effect of the stray capacitance

c)       Minimizing the effect of intercomponent capacitance

d)      Eliminating all the node to earth capacitances

30.   Vibration galvanometers, tunable amplifiers and head phones are used in

a)      Dc bridges

b)      Ac bridges

c)       Both dc and ac bridges

d)      Kelvin double bridge

31.   Illumination is measured using which one of the following?

a)      Millivoltmeter

b)      Stroboscope

c)       Luxmeter

d)      pH meter

32.   In a CRO, the time-base generators supply ramp voltage to

a)      Horizontal deflecting plates

b)      Vertical deflecting plates

c)       Both horizontal and vertical deflecting plates

d)      None of the above

33.   In a CRT the highest positive potential is given to

a)      Focusing electrodes

b)      Cathode

c)       Vertical deflection plates

d)      Post deflection acceleration anode

34.   In a dual beam oscilloscope

a)      There are two separate vertical inputs and two separate horizontal inputs

b)      There are two separate vertical inputs and there is only one set of horizontal deflection plates

c)       There is only one vertical input but there are two separate horizontal deflection plates

d)      There is only one vertical and one horizontal input

  

35.   The conversion of a voltage value to a time interval is carried out by comparing the unknown voltage with a voltage ramp in a

a)      Ramp type DVM

b)      Integrating type DVM

c)       Continuous type DVM

d)      Successive approximation type DVM