Measurement and Instrumentation Objective Questions – Part 5

a) Active
b) Passive
c) Secondary
d) Inverse

Ans : (a)

2. The transducers that converts the input signal into the output signal, which is a discrete function of time is known as ______ transducer.

a) Active
b) Analog
c) Digital
d) Pulse

Ans : (c)

3. A transducer that converts measurand into the form of pulse is called

a) Active transducer
b) Analog transducer
c) Digital transducer
d) Pulse transducer

Ans : (d)

4. Which of the following is a digital transducer?

a) Strain gauge
b) Encoder
c) Thermistor
d) LVDT

Ans : (b)

5. Strain gauge, LVDT and thermocouple are examples of

a) Active transducers
b) Passive transducers
c) Analog transducers
d) Primary transducers

Ans : (c)

6. An inverse transducer is a device which converts

a) An electrical quantity into a non electrical quantity
b) Electrical quantity into mechanical quantity
c) Electrical energy into thermal energy
d) Electrical energy into light energy

Ans : (a)

7. A strain gauge is a passive transducer and is employed for converting

a) Mechanical displacement into a change of resistance
b) Pressure into a change of resistance
c) Force into a displacement
d) Pressure into displacement

Ans : (a)

8. Resolution of a transducer depends on

a) Material of wire
b) Length of wire
c) Diameter of wire
d) Excitation voltage

Ans : (c)

9. The sensitivity factor of strain gauge is normally of the order of

a) 1 to 1.5
b) 1.5 to 2.0
c) 0.5 to 1.0
d) 5 to 10

Ans : (b)

10. In wire wound strain gauges, the change in resistance is due to

a) Change in diameter of the wire
b) Change in length of the wire
c) Change in both length and diameter
d) Change in resistivity

Ans : (c)

11. Bonded wire strain gauges are

a) Exclusively used for construction of transducers
b) Exclusively used for stress analysis
c) Used for both stress analysis and construction of transducer
d) Pressure measurement

Ans : (c)

12. Certain type of materials generates an electrostatic charge or voltage when mechanical force is applied across them. Such materials are called

a) Piezo-electric
b) Photo-electric
c) Thermo-electric
d) Photo-resistive

Ans : (a)

13. Quartz and Rochelle salt belongs to _______ of piezo-electric materials

a) Natural group
b) Synthetic group
c) Natural or Synthetic group
d) Fiber group

Ans : (a)

14. Which of the following are piezo electric substances?

1. Barium titanate
2. Lead titanate
3. Lead Zirconate
4. Cadmium and sulphate

Choose correct one

a) 1,2 and 4
b) 1,3and4
c) 1,2and 3
d) 2,3and 4

Ans : (c)

15. Piezo-electric transducers are

a) Passive transducers
b) Inverse transducers
c) Digital transducers
d) Pulse transducers

Ans : (b)

16. Piezo – electric transducers work when we apply ________ to it.

a) Mechanical force
b) Vibrations
c) Illuminations
d) Heat

Ans : (a)

17. Piezo electric crystal can produce an emf

a) When external mechanical force is applied to i
b) When radiant energy stimulates the crystal
c) When external magnetic field is applied
d) When the junction of two such crystals are heated

Ans : (a)

18. The draw backs of strain gauges are

S1: Low fatigue life
S2: They are expensive, brittle and sensitive to temperature
S3: Poor linearity

Choose the correct one

a) S1 and S2
b) S2 and S3
c) S1 and S3
d) S1 only

Ans : (b)

19. LVDT windings are wound on

a) Steel sheets
b) Aluminium
c) Ferrite
d) Copper

Ans : (c)

20. The size of air cored transducers in comparison to the iron core parts is

a) Smaller
b) Larger
c) Same
d) Unpredictable

Ans : (b)

21. The principle of operation of LVDT is based on the variation of

a) Self inductance
b) Mutual inductance
c) Reluctance
d) Permanence

Ans : (b)

22. LVDT is an/a _______ transducer

a) Magneto-strict ion
b) Inductive
c) Resistive
d) Eddy current

Ans : (b)

23. Which of the following can be measured with the help of piezo electric crystal?

a) Force
b) Velocity
c) Sound
d) Pressure

Ans : (a)

24. S1: Transducer is a device which converts physical into electrical quantity
S2: Transducer is also called as sensor.

a) S1 is true & S2 is false
b) S2 is true & S1 is false
c) Both S1 & S2 are true
d) Both S1 & S2 are false

Ans (b)

27. In a LVDT, the two secondary voltages

a) Are independent of the core position
b) Vary unequally depending on the core position
c) Vary equally depending on the core position
d) Are always in phase quadrature

Ans : (b)

28. Capacitive transducers are normally employed for_________ measurements

a) Static
b) Dynamic
c) Transient
d) Both static and dynamic

Ans : (b)

29. Match the following

1. EEG A. Diagnostic tool for heart alignment
2. ECG B. Diagnostic tool for brain alignment
3. Sphygmo-manometer C. Instrument used for measuring blood pressure
4. Stethoscope D. instrument used to hear pulse/heart beat

Choose the correct one

a) 1- B, 2 – A, 3 – C, 4 – D
b) 1 – B, 2 – A, 3 – D, 4 – C
c) 1- C, 2 – A, 3 – B, 4 – D
d) 1 – A, 2 – B, 3 – C, 4 – D

Ans : (a)

30. Pick the correct statement regarding functions of a transducer

S1: Sense the magnitude, change in & / or frequency of same measurand
S2: To provide electrical output that furnishes accurate, quantitative data about the measurand

a) S1 is true & S2 is false
b) S2 is true & S1 is false
c) Both S1 & S2 are true
d) Both S1 & S2 are false

Ans : (c)

31. The transducers which requires an external power and their output is a measure of some variation such as resistance, inductance, capacitance etc., are called as

a) Active transducer
b) Primary sensor
c) Passive transducer
d) Self generating transducer

Ans : (c)

32. The principle of operation of variable resistance transducer is

a) Deformation leads to change in resistance
b) Displacement of a contact slider on a resistance
c) Coupling of two coils changes with displacement
d) Movement of magnetic field produces variation in resistance of material

Ans : (b)

33. The application of LVDT is

a) Joint motion
b) Finger movement
c) Limb movement
d) Heart wall motion

Ans : (c)

34. Venturi is associated with

a) Venous blood pressure
b) Digital plethysmography
c) Dialysate flow in artificial kidney
d) Blood flow in heart lung machine

Ans : (d)

35. Pressure transducer for measuring blood pressure is

a) Strain gauge transducer only
b) Strain gauge or capacitive transducer
c) Resistive transducer
d) Fiber optic transducer

Ans : (b)

36. The change in resistance of a metal wire owing to strain is due to

S1: Change in dimension of wire expressed by factor (1-2µ)
S2: Change in resistance ?

a) S1 is true & S2 is false
b) S2 is true & S1 is false
c) Both S1 & S2 are true
d) Both S1 & S2 are false

Ans : (b)

37. In foil strain gauge the thickness of foil varies from

a) 2.5 micron to 6 micron
b) 25 micron (or) less
c) 25 micron to 60 micron
d) 2.5 micron to 5 micron

Ans : (a)

38. Photo conductive cell consists of a thin film of

a) Quartz
b) Lithium sulphate
c) Barium titanate
d) Selenium

Ans : (d)

39. S1: In multimode fiber optics, intensity modulating schemes can be employed.
S2: Schemes using polarizing techniques need birefringent fiber.

a) S1 is true and S2 is false
b) Both S1 and S2 are true
c) S1 is false and S2 is true
d) Both S1 and S2 are false

ans (b)

40. Test electrode is also known as

a) Indicator electrode
b) Reference electrode
c) Second electrode
d) Primary electrode

Ans : (a)

41. Most commonly used indicator electrode is

a) Calomel electrode
b) Silver electrode
c) Silver – Silver chloride electrode
d) Glass electrode

Ans : (d)

42. _________ is the example of photo emissive cell.

a) LDR
b) Photo diode
c) Photo transistor
d) Photo multiplier

Ans : (a)

43. pH value of venous blood is

a) 7.30
b) 7.40
c) 7.35
d) 7.45

Ans : (c)

44. Silver chloride electrode is used as a reference electrode due to its

a) Large half cell potential
b) Stable half cell potential
c) Stable resting potential
d) Stable action potential

Ans : (b)

45. The capacitance microphone is used for the detection of

a) Heart rate
b) Blood flow
c) Heart sound
d) Foot pressure

Ans : (c)

46. In a graded index fiber, the total reflected light takes a _________

a) Straight line path
b) Parabolic path
c) Elliptical path
d) Circular path

Ans (b)

47. ________ fiber is used in interferometric instruments.

a) Monomode
b) Multimode
c) Birefringent
d) Coated

Ans (a)

48. Fiber optic sensor can be used to sense _________

a) Displacement
b) Power
c) Current
d) Resistance

Ans (a)

49. Photo multiplier consists of

a) 1 Photo emissive cathode & 2 dynodes
b) 2 Photo emissive cathodes & 2 dynodes
c) 2 Photo emissive cathodes & 1 dynode
d) 1 Photo emissive cathode & 1 dynode

Ans : (a)

50. The resistance of LDR ______ when exposed to radiant energy.

a) Remains unaltered
b) Increases
c) Reaches maximum
d) Decreases

Ans : (d)