Multiple choice question for engineering
Set 1
1. Thermocouple is a ______________
a) Primary device
b) Secondary transducer
c) Tertiary transducer
d) None of the mentioned
Answer
Answer: a [Reason:] Thermocouple is a device which converts thermal energy to electrical energy and it can be treated as primary device.
2. Operation of thermocouple is governed by _______________
a) Peltier effect
b) Seebeck effect
c) Thomson effect
d) All of the mentioned
Answer
Answer: d [Reason:] Operation of thermocouple is based on three major effects- Peltier, Thomson and seebeck, all describes relation between current flow and temperature between two different metal.
3. ______________ describes current flow between two junctions formed by two different metals.
a) Peltier effect
b) Thomson effect
c) Seebeck effect
d) None of the mentioned
Answer
Answer: a [Reason:] When two different metals are connected to form two junctions, current flow will occur from one junction to other. This is described by peltier effect.
4. Amount of heat liberated or absorbed when 1A current passes is called ____________
a) Thomson coefficient
b) Peltier coefficient
c) Seebeck coefficient
d) None of the mentioned
Answer
Answer: b [Reason:] Peltier coefficient relates heat liberated or absorbed and current flow.
5. Total seebeck effect can be found as _____________
a) Total peltier effect
b) Total Thomson effect
c) Partly peltier and partly Thomson effect
d) None of the mentioned
Answer
Answer: c [Reason:] All three effects, peltier, seebeck and Thomson effects are connected each other, and total seebeck effect can be found as partly peltier and partly Thomson effect.
6. Which of the following element is used as thermocouple in nuclear reactor?
a) Boron
b) Platinum
c) Copper
d) Iron
Answer
Answer: a [Reason:] Nuclear reactors are places where large amount of heat is liberated, here boron is used as thermocouple element as it can measure temperature above 15000c.
7. Thermocouple cannot used for measurement of temperature of liquid.
a) True
b) False
Answer
Answer: b [Reason:] Immersion type thermocouple can be used to measure temperature of liquid, in which thermocouple is immersed in liquid.
8. _________________ can be used as a replacement for thermocouple lead.
a) Replacement lead
b) Replica lead
c) Compensating lead
d) None of the mentioned
Answer
Answer: c [Reason:] Compensating leads are of same materials as thermocouple leads and can be used as a replacement.
9. Thermo couple cannot be used to measure ____________
a) Temperature of gas
b) Temperature of liquid
c) IR radiation
d) None of the mentioned
Answer
Answer: d [Reason:] Infra-Red radiation is characterized by temperature and thermocouple can be used to measure temperature.
10. Peltier effect is reverse of seebeck effect.
a) True
b) False
Answer
Answer: a [Reason:] Peltier effect and seebeck effect operations are reverse to each other.
Set 2
1. Which of the following represents moment of inertia of force acting tangential to a cylindrical rod?
a) FR
b) F/R
c) F2R
d) FR2
Answer
Answer: a [Reason:] Moment of inertia of force acting tangential to a rod is the product of force and radius of rod.
2. Which of the following devices can be used for measuring torque?
a) Helical spring
b) Flat spiral spring
c) Bellows
d) Diaphragm
Answer
Answer: b [Reason:] Flat spiral springs are, flat springs which are fixed at center and force is applied on the peripheral end.
3. Which of the following can be well suited for flat-spiral spring device?
a) Used for very low torque range
b) Used for very high torque range
c) Used for all ranges of torque
d) None of the mentioned
Answer
Answer: a [Reason:] Flat spiral spring devices is only applicable for very low range of torque measurement since high range of force may break the device.
4. ___________ is used for measuring torque in rotating parts in machines.
a) Accelerometer
b) Dynamometer
c) Tachometer
d) None of the mentioned
Answer
Answer: b [Reason:] Dynamometers are the devices which are used to measure torque in rotating parts of machines, mainly torque of rotating shafts.
5. Square cross sectional torsions bars are preferable than circular cross sectional torsion bars.
a) True
b) False
Answer
Answer: a [Reason:] Due to higher mechanical stability provided by square cross sectional torsion bars, they are highly preferable than circular cross sectional.
6. Which of the following is true for torque measurement?
a) Measurement of applied force only
b) Measurement of length of arm
c) Measurement of force and length of arm
d) Measurement of velocity of material
Answer
Answer: c [Reason:] Torque can be measured as the product of applied force and length of arm. Hence both of the parameters are important in measurement of torque.
7. Which of the following represents correct relationship between angular displacement and torque?
a) Direct proportionality
b) Inverse proportionality
c) Equal magnitude
d) None of the mentioned
Answer
Answer: a [Reason:] Torque of a bar is proportional to force applied tangential to bar, and hence torque can be treated as direct proportional with angular displacement.
8. Torque can be measured using surface shear strains.
a) True
b) False
Answer
Answer: a [Reason:] Torque can also be measured using measuring surface shear strains of the material. Merit of this system is that, it is independent of temperature variations.
9. Which of the following represents correct position of strain gauges in torque measurement?
a) 900 with each other
b) Parallel to shaft axis
c) Perpendicular to shaft axis
d) 450 from shaft axis
Answer
Answer: d [Reason:] All strain gauges are positioned 450 equally from shaft axes, such an arrangement causes insensitivity to bending or axial stress.
10. A torsion bar of constant inner radius and length is applied with constant torque. What will happen for the angular displacement if outer radius of torsion bar is increased?
a) Increase
b) Decreases
c) Doubles
d) Halved
Answer
Answer: b [Reason:] Relation between angular displacement and radius of torsion bar can be explained using expression:
ɸ= 2LT/πG(R04 – Ri4)
keeping all other factors constant, angular displacement and outer radius becomes inverse portioned to each other.
Set 3
1. Which of the following is not a characteristic of ideal transducer?
a) High dynamic range
b) Low linearity
c) High repeatability
d) Low noise
Answer
Answer: b [Reason:] An ideal transducer should show high linearity. A linear system should produce exact output according to input.
2. A transducer converting ground movement or velocity to voltage is known as ________________
a) Geophone
b) Pickup
c) Hydrophone
d) Sonar transponder
Answer
Answer: a [Reason:] Geophone is a device used to convert ground movement to voltage, which is used in Remote ground sensors (RGS) and also as a replacement for broadband seismometers.
3. Which of following represent active transducer?
a) Strain gauge
b) Thermistor
c) LVDT
d) Thermocouple
Answer
Answer: d [Reason:] Active transducers are self-generating type, they don’t require external power to work while passive transducers require external power to work.
4. Which transducer is known as ‘self-generating transducer’?
a) Active transducer
b) Passive transducer
c) Secondary transducer
d) Analog transducer
Answer
Answer: a [Reason:] The name self-generating transducer is due to its property of working without the use of external power.
5. What is the relation between scale factor and sensitivity of a transducer?
a) Scale factor is double of sensitivity
b) Scale factor is inverse of sensitivity
c) Sensitivity is inverse of scale factor
d) Sensitivity is equal to scale factor
Answer
Answer: b [Reason:] Sensitivity is an important property of transducer. Every transducer should be sufficiently sensitive to provide some output that can be detected.
6. Which of the following is an analog transducer?
a) Encoders
b) Strain gauge
c) Digital tachometers
d) Limit switches
Answer
Answer: b [Reason:] Analog transducers convert physical quantity to analog signals while digital transducers convert physical quantity to digital signals. Strain gauge is an example of Analog transducer.
7. What is the principle of operation of LVDT?
a) Mutual inductance
b) Self-inductance
c) Permanence
d) Reluctance
Answer
Answer: a [Reason:] Linear variable differential transformer (LVDT) is type of transformer used for measuring displacement, and it has same principle of operation of transformer.
8. Which of the following can be measured using Piezo-electric transducer?
a) Velocity
b) Displacement
c) Force
d) Sound
Answer
Answer: c [Reason:] Piezo-electric crystals produces electric signal when pressure applied. Examples are quartz, Rochelle salt. That is, it converts force into electric signals.
9. Capacitive transducer are used for?
a) Static measurement
b) Dynamic measurement
c) Transient measurement
d) Both static and dynamic
Answer
Answer: b [Reason:] Capacitive transducers convert measurant into changes in capacitance. Change in capacitance is caused by change in dielectric or change in distance between plates.
10. Which of the following is used in photo conductive cell?
a) Selenium
b) Quartz
c) Rochelle salt
d) Lithium sulphate
Answer
Answer: a [Reason:] Photo conductive action is the property of reduction of resistance when exposed to light. Selenium shows photoconductive action.
Set 4
1. Which of the following represents slow motion of layers of fluid in one direction?
a) Laminar flow
b) Turbulent flow
c) Viscous flow
d) Both laminar and viscous flow
Answer
Answer: d [Reason:] If different layers of fluid moves slowly in a single direction, it is known as laminar flow which can also be called as viscous flow.
2. If shear stress is equal proportional to velocity gradient, fluid is called as ______________
a) Newtonian fluid
b) Viscous fluid
c) Laminar fluid
d) None of the mentioned
Answer
Answer: a [Reason:] Newtonian fluids are in which shear stress is proportional to velocity gradient. Velocity gradient is the result of approach of shear stress and is considered to be the rate of deformation.
3. Which of the following represents newton’s equation for viscosity?
a) τ=µ(dv/dt)
b) µ=τ(dv/dt)
c) τ=dv/dt
d) τ= µ2(dv/dt)
Answer
Answer: a [Reason:] Newton’s equation for viscosity connects relation of viscosity and velocity gradient.
4. Which of the following represents relation for kinematic viscosity?
a) Absolute density/mass density
b) Absolute density × mass density
c) Absolute density × (mass density)2
d) Absolute density/(mass density)2
Answer
Answer: a [Reason:] Kinematic density is the ratio of absolute viscosity and mass density denoted by ‘ϱ’.
5. Which of the following represents Newtonian fluids?
a) Lubricating oils
c) Honey
c) Rubber suspension
d) Synthetic oils
Answer
Answer: a [Reason:] Newtonian fluids are in which shear stress proportional to velocity gradient. Lubricating oils are Newtonian fluid, while all other options represents non-Newtonian fluids.
6. What happens to viscosity of liquid and gas when temperature is increased?
a) Both increases
b) Both decreases
c) For liquid increases and for gas decreases
d) For liquid decreases and gas increases
Answer
Answer: d [Reason:] As temperature is increased, viscosity of liquid decreases and for gases viscosity increases.
7. Orifice type viscometer covert viscosity to _______________
a) Force
b) Pressure
c) Displacement
d) Potential difference
Answer
Answer: b [Reason:] Orifice type device is used for measurement of viscosity in which viscosity is converted to pressure change.
8. Rotameter type viscometer convert viscosity to angular displacement.
a) True
b) False
Answer
Answer: b [Reason:] Rotameter type viscometers are used for measurement of viscosity and they are working based on the conversion of viscosity to torque.
9. Which of the following is not converting viscosity to pressure?
a) Redwood viscometer
b) Saybolt viscometer
c) Orifice viscometer
d) Rotameter viscometer
Answer
Answer: d [Reason:] Rotameter viscometer convert viscosity to torque, while all other options are different names of same viscometer which convert viscosity to pressure.
10. Which of the following represents Hagen-poissule equation?
a) µ= (πd4ΔP)/ (128Q’L)
b) µ= (d4ΔP)/ (128Q’L)
c) µ= (πd4ΔP)/ (Q’L)
d) µ= (πd4)/ (128Q’L)
Answer
Answer: a [Reason:] Hagen-Piossule equation is applied in viscosity measurement using Saybolt viscometer.
Set 5
1. A Multimeter is used to measure___________
a) Only AC current
b) Only DC voltage
c) Both AC and DC quantities
d) Resistance only
Answer
Answer: c [Reason:] Multimeter is a device which can be used to measure both AC and DC quantities and also resistance.
2. Which of the following device can be used to measure low voltage?
a) VTVM
b) Moving iron voltmeter
c) CRO
d) None of the mentioned
Answer
Answer: c [Reason:] CRO (Cathode ray oscilloscope) is a device which can be used to measure voltage level of signals with wide range of variation.
3. Which of the following applications are electrostatic instruments suited for?
a) With AC quantities only
b) With AC and DC quantities
c) With DC quantities only
d) None of the mentioned
Answer
Answer: b [Reason:] Electrostatic instruments are devices which can be used in both AC and DC quantities.
4. Which of the following unit is used to express sensitivity of analog voltmeter?
a) Ohms
b) Voltage
c) No unit
d) Ohms per volt
Answer
Answer: d [Reason:] Sensitivity of analog voltmeter is expressed in terms of ohms per volt. That is number of Ω resistance in meter circuit divided by the full scale measured value.
5. In a CRO what is the purpose of blanking circuit?
a) To increase visual quality
b) To increase number of channels
c) To eliminate retrace of signals due to movement of spot
d) None of mentioned
Answer
Answer: c [Reason:] Blanking circuit is used to eliminate retrace of signals when spot moves from left to right.
6. Who invented first digital voltmeter?
a) Edward Lawry Norton
b) Andrew Kay
c) Joseph Henry
d) Nicola tesla
Answer
Answer: b [Reason:] Digital voltmeter gives output reading on digital format. It was invented by Andrew Kay.
7. Which of the following can be the range of input impedance of voltmeter?
a) less than 1Ω
b) Between 1Ω and 10Ω
c) Very high
d) unpredictable
Answer
Answer: c [Reason:] Input impedance of volt meter is of the order of 10MΩ. That is very high. Voltmeter has a high shunt resistance value.
8. What is the purpose of differential amplifier in voltmeter?
a) Elimination of unwanted signals
b) To find difference of voltages
c) To eliminate DC components
d) To set a certain voltage level
Answer
Answer: a [Reason:] Differential amplifiers is included in voltmeters to avoid any spurious signals, which may arise due to electrostatic stray field.
9. In a CRO to which part saw tooth waveform is applied?
a) Horizontal amplifier
b) To fluorescent screen
c) Vertical deflection plate
d) Electron gun
Answer
Answer: a [Reason:] Saw tooth wave is applied to horizontal amplifier of CRO. Horizontal amplifier controls horizontal deflection plates.
10. What will be the sensitivity of a volt meter with 0 to 7mA meter movement?
a) 143 Ω/ V
b) 140 Ω/V
c) 100 Ω/V
d) 10 Ω/V
Answer
Answer: a [Reason:] Sensitivity of a voltmeter is the reciprocal of maximum current deflection. It is expressed in unit Ω/V. here sensitivity is reciprocal of 7mA.