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# Multiple choice question for engineering

## Set 1

1. Inverse transducers are also known as _________________
a) Open loop transducers
b) Closed loop transducers
c) Input transducers
d) Output transducers

Answer: d [Reason:] Output transducers are which converts electrical quantity to non-electrical quantity, known as inverse transducers.

2. A system with feedback loop doesn’t have ______________
a) Less stability
b) High linearity
c) Zero-order operation
d) All of the mentioned

Answer: a [Reason:] For a system feedback loop is provided to ensure high stability, linearity.

3. Which of the following represents torque produced in a PMMC device?
a) BAI0
b) BNI0
c) BANI0
d) BA2NI0

Answer: c [Reason:] B represents flux density in the air gap, A represents area of moving coil and N represents number of turns in the moving coil.

4. Inverse transducer is system which converts _________________
a) Electrical quantity to non-electrical quantity
b) Non-electrical quantity to electrical quantity
c) Electrical quantity to electrical quantity itself
d) Non- electrical quantity to non-electrical quantity itself

Answer: a [Reason:] Transducers are devices which transfers measurand which will be a non-electrical quantity to electrical quantity. Inverse transducers are the devices operating just opposite to transducers.

5. In a PMMC device what change will happen to torque, if flux density increased?
a) Increases
b) Decreases
c) Remain constant
d) None of the mentioned

Answer: a [Reason:] In torque equation of a PMMC device torque and flux density have a direct proportionality. Tf=BANI0 Where Tf is the torque and B is the flux density.

6. PMMC devices are converters of _____________
a) Voltage to force
b) Force to voltage
c) Force to force
d) Voltage to voltage

Answer: a [Reason:] Permanent Magnet Moving coil converts input electrical quantity to force or torque in needle system.

7. In PMMC device, torque and number of turns have _______________
a) Inverse proportionality
b) Direct proportionality
c) Equality
d) Undetermined

Answer: b [Reason:] Torque equation is Tf=BANI0, Where Tf is the torque and N is the number of turns.

8. Which of the following is an inverse transducer _____________
a) Piezoelectric transducer
b) LVDT
d) Bourdon tube

Answer: a [Reason:] Piezo electric transducers are devices which are capable of converting electrical quantity to non-electrical quantity, which is an inverse transducer.

9. Input transducers and inverse transducers are same.
a) True
b) False

Answer: b [Reason:] Input transducers are devices which convert non-electrical quantity to electrical quantity and Inverse transducers are devices which convert electrical quantity to non-electrical quantity.

10. Which of the following cannot act as inverse transducer?
a) Quartz
b) Barium titanate

Answer: d [Reason:] Quartz, Barium titanate and Lead zirconate are piezo electrical substances which are known for its ability to act as inverse transducers.

## Set 2

1. Which of the following are nuclear radiations?
a) Beta
b) Alpha
c) Gamma
d) All of the mentioned

Answer: d [Reason:] Beta, alpha, and gamma particles are emitted from radioactive materials and they are known as nuclear radiations.

2. Which of the following has helium nucleus?
a) Alpha particle
b) Beta particle
c) Gamma particle
d) All of the mentioned

Answer: a [Reason:] Alpha particles has a positive charge of 2 and relative mass of 4 which is similar to helium nucleus.

3. Which of the following represents sensitivity of ionization transducer?
a) Ia/Ig
b) Ig/Ia
c) IaIg
d) Ia/ PIg

Answer: d [Reason:] Ia is the anode current and Ig is the grid current, P is the absolute pressure of gas.

4. Which of the following potential is applied to grid?
a) +ve potential
b) –ve potential
c) Neutral potential
d) None of the mentioned

Answer: a [Reason:] Grid is applied by a +ve potential of 100v in order to attract electrons.

5. Which of the following is correct for ionization transducer?
a) Grid current decrease constantly
b) Grid current Increases constantly
c) Grid current is made constant
d) None of the mentioned

Answer: c [Reason:] Grid current and primary electrons are always held constant and variations in anode current is measured.

6. Cold cathode ionization vacuum gauges are more accurate than hot cathode ionization vacuum gauges.
a) True
b) False

Answer: b [Reason:] Cold cathode vacuum gauges are less accurate than hot cathode vacuum gauges, But some difficulties in hot cathode are reduced in cold cathode type.

7. Which of the following cannot be measured using ionization transducer?
a) Vacuum pressure
b) Gaseous pressure
c) Displacement
d) None of the following

Answer: d [Reason:] Ionization transducers can be used for measurement of displacement also.

8. Which of the following applications ionization chamber is used?
a) For detection of nuclear radiation
b) For better stability
c) For storing inert gas
d) For ionizing gas

Answer: a [Reason:] Ionization chambers in transducers are used for detection and measurement of nuclear radiation.

9. Which of the following is a radioactive vacuum gauge?
a) Cold cathode gauge
b) Hot cathode gauge
c) Non ionization gauge
d) None of the mentioned

Answer: a [Reason:] Radioactive vacuum gauge is a cold cathode type gauge which is also based on ionization of gas.

10. Which of the following represents mass absorption coefficient?
a) Ratio of linear absorption coefficient to density
b) Product of absorption coefficient and density
c) Linear absorption coefficient
d) Product of linear absorption coefficient and mass

Answer: a [Reason:] Ratio of linear absorption coefficient and density is known as mass absorption coefficient.

## Set 3

1. Which of the following conversions take place in float element?
a) Level to force
b) Level to voltage
c) Level to displacement
d) None of the mentioned

Answer: c [Reason:] Float elements are used for measuring liquid level of a system. Liquid level indication is obtained using displacement of float element.

2. In ______________ system, float whose weight greater than liquid to be displaced is used.
a) Inverse float system
b) Displacer system
c) Magnifying float system
d) None of the mentioned

Answer: b [Reason:] Displacer systems are in which weight of float will be greater than weight of liquid to be displaced.

3. For float element, uniformity of density is important.
a) True
b) False

Answer: b [Reason:] While using float element, liquid of uniform density distribution is not required. But in displacer system, liquid with constant density distribution is important.

4. Which of the following represents pressure of a liquid column with constant density?
a) ϱgh
b) ϱh
c) ϱg
d) None of the mentioned

Answer: a [Reason:] In a liquid column with constant density ‘ϱ’, pressure can be represented as product of density, acceleration due to gravity and height of liquid column.

5. Which of the following is correct for level to force conversions?
a) Liquid at constant density distribution
b) Liquid with different density distribution
c) Level difference should be gradual
d) Liquid should be highly viscous

Answer: a [Reason:] Liquid used for level to force conversion should have constant density distribution at all points, it enables consistent measurement of force.

6. Which of the following devices are used for level to force conversion?
b) Membrane
c) Diaphragm
d) Voltmeter

Answer: a [Reason:] Load cells are force measuring devices, and they are used for level to force conversion.

7. Diaphragm element is used for level to pressure conversion.
a) True
b) False

Answer: a [Reason:] Diaphragm elements are used for measuring pressure and they are used for level to pressure conversion.

8. In closed container type level measuring system, pressure at top of container is due to ______________
a) Vacuum pressure
b) Vapor pressure
c) Liquid pressure
d) Atmospheric pressure

Answer: b [Reason:] Pressure at top of container in closed container system is the pressure above liquid level which is the pressure of vapor.

9. What will happen if the float becomes lighter?
a) Density variations becomes more important
b) Density variations becomes less important
c) System becomes less efficient
d) None of the mentioned

Answer: b [Reason:] When float made lighter, errors due to density variation decreases.

10. Which of the following represents correct relation for pressure in manometer type level measuring system?
a) (ϱmhm– ϱy)g
b) (ϱm– ϱy)g
c) (ϱmhm– ϱ)g
d) ϱmhm– ϱy

Answer: a [Reason:] (ϱmhm– ϱy)g represents pressure difference in a manometer system for measuring level measuring, where ϱm is the density of manometric liquid and hm is the level of manometric liquid.

## Set 4

1. Which of the following represents correct conversion for magnetostrictive transducers?
a) Mechanical energy to magnetic energy
b) Mechanical energy to electrical energy
c) Magnetic energy to electrical energy
d) Mechanical energy to acoustic energy

Answer: a [Reason:] Transducers which convert mechanical energy to magnetic energy is known as magnetostrictive transducers.

2. Which of the following represents negative magnetostriction?
a) On increasing stress permeability decreases
b) On decreasing stress permeability decreases
c) On increasing stress conductivity decreases
d) None of the mentioned

Answer: a [Reason:] In negative magnetostrictive materials as stress applied is increased, magnetic properties like remnant magnetic field and permeability increases.

3. Which of the following element shows increase in magnetic flux density on decreasing stress applied?
a) Nickel Iron alloy
b) Nickel
c) Both Nickel and Nickel iron alloy
d) None of the mentioned

Answer: b [Reason:] Nickel in its pure form shows inverse proportionality between stress and magnetic flux density, while Nickel Iron alloy shows direct proportionality between stress and magnetic flux density.

4. Which of the following materials shows increase in permeability with increase in tensile stress?
a) Negative magnetostriction materials
b) Non magnetostriction materials
c) Positive magnetostriction materials
d) None of the mentioned

Answer: c [Reason:] Positive magnetostriction materials are those which exhibits direct proportionality between permeability and applied stress.

5. Magnetostrictive transducer can be used to measure _______________
a) Force
b) Acceleration
c) Torque
d) All of the mentioned

Answer: d [Reason:] Magnetostrictive transducers can be used to measure a wide variety of quantities like force, acceleration, torque etc.

6. Which of the following represents use of including additional mass in acceleration transducer?
a) To prevent system response to transverse acceleration
b) To prevent system response to linear acceleration
c) To prevent system response to angular acceleration
d) None of the mentioned

Answer: a [Reason:] Additional mass is included in the magnetostrictive acceleration transducers for avoiding effects of transverse acceleration.

7. Magnetostrictive transducers are more sensitive than piezoelectric transducers.
a) True
b) False

Answer: b [Reason:] Due to the action of earth magnetic field magnetostrictive transducers became less sensitive than piezoelectric transducer.

8. Which of the following torque can be measured using magnetostrictive transducers?
a) Large amplitude torque
b) Small amplitude torque
c) Torque of an amplitude
d) Cannot be used to measure torque

Answer: b [Reason:] Magnetostrictive torque transducers are suitable for measuring time varying small amplitude torques only.

9. Which of the following represents correct expression for sensitivity in a magnetostrictve transducer?
a) ΔB
b) ΔB/σ
c) σ
d) σ/ΔB

Answer: b [Reason:] Sensitivity of a magnetostrictive transducer is the ratio of change in magnetic flux density and applied stress.

10. Magnetostrictive transducers can only be used in static forces.
a) True
b) False

Answer: b [Reason:] Magnetostrictive force transducers can be used in case both static and dynamic forces.

## Set 5

1. Science of precise and accurate measurement of various physical quantities is termed as___________
a) Metrology
b) Meteorology
c) Pedology
d) Mineralogy

Answer: a [Reason:] Metrology is the science of measurement. Metrology includes all theoretical aspects of measurement. Meteorology is the branch of study about atmosphere. Pedology is the branch of study about soil and Mineralogy is a branch of geology specializing in chemistry, chemical structure and physical properties of minerals.

2. In a measuring system quantity under measurement is termed as ________________
a) Measurand
b) Controllers
c) Sensors
d) Indicators

Answer: a [Reason:] Measurand is the value under consideration in a measuring system. For example while measuring signal voltage, voltage is the measurand.

3. In a measurement, what is the term used to specify the closeness of two or more measurements?
a) Precision
b) Accuracy
c) Fidelity
d) Threshold

Answer: a [Reason:] Closeness of two or more measurements is termed as precision. For example, if two measurement gives 3.1kg as output, then the measurement is said to be more precise.

4. Comment true or false: ‘Accuracy and Precision are dependent on each other’.
a) True
b) False

Answer: b [Reason:] Accuracy is the closeness of a measured value with a standard value. Precision is the closeness of two or more measured values. Hence they are not dependent with each other.

5. During a measurement, for a measure value “B”, absolute error is obtained as “A”, what will be the relative error of measurement?
a) A/B
b) B/A
c) (A+1)/B
d) (B+A)/A

Answer: a [Reason:] Ratio of absolute error to measured value is called relative error. i.e. Relative error= (Absolute error) / (Measured value).

6. In a measuring system what is the term used to specify difference between higher and lower calibration values?
a) Range
b) Span
c) Drift
d) Threshold

Answer: b [Reason:] Span is the difference between higher and lower calibration values. For an instrument with range 100 units to 250 units span is 150 units.

7. Using a voltmeter measured value is 24.3V, while its true value is 24V. What is the relative error of measurement?
a) 1.25%
b) 1.2%
c) 1.3%
d) 1.4%

Answer: a [Reason:] Relative error= ((measured value-true value)/true value)*100% Given measured value is 24.3V and true value is 24V, using given equation relative error is obtained.

8. ______________ is used to prevent oscillation in moving system
a) Oscillatory system
b) Controlling
c) Damping system
d) Deflecting

Answer: c [Reason:] Damping system acts on damping force. Damping force is necessary in case of moving systems to bring the pointer to rest quickly.

9. What is the span of an ammeter with range -30 to +30A?
a) 60
b) -60
c) 30
d) 20

Answer: a [Reason:] Span of a system is the difference between higher and lower calibrated values. Here span=30-(-30) =60.

10. Given a DC voltmeter has a sensitivity of 500ohm/V. For a full scale reading in 100V range, what will be the current through voltmeter?
a) 500mA
b) 200mA
c) 250mA
d) 300mA

Answer: b [Reason:] Full scale reading in 100V range means 100V itself. For a sensitivity of 500ohm/V current through it will be ratio of scale reading and sensitivity.ie,0.2A=200mA.

11. What will be the sensitivity of a voltmeter for 0 to 50mA meter movement?
a) 20ohm/V
b) 25ohm/V
c) 50ohm/V
d) 5ohm/V

Answer: a [Reason:] Sensitivity of a voltmeter is the reciprocal of full scale deflection of current. Here current deflection is given by 0 to 50mA and sensitivity is 20ohm/V.

12. Using an instrument for measuring capacitance gives an output 203.5nF whereas true value is 203.9nF. What will be the static correction of instrument?
a) -0.4nF
b) 0.4nF
c) 1nF
d) 0.5nF