# Comparators - Mechanical Engineering (MCQ) questions and answers

1)   Johansson mickrocator is a type of

a. mechanical optical comparator
b. mechanical comparator
c. optical comparator
d. electrical comparator
 Answer  Explanation ANSWER: mechanical comparator Explanation: No explanation is available for this question!

2)   Which of the following statements are true?

1. Mechanical comparators are compact and easy to handle
2. Parallax error is never observed in mechanical comparator
3. Sigma comparator is a type of mechanical comparator
4. Mechanical comparators have low inertia which makes them sensitive to vibrations

a. 1 and 2
b. 3 and 4
c. 1 and 3
d. All of the above
 Answer  Explanation ANSWER: 1 and 3 Explanation: No explanation is available for this question!

3)   Which type of comparator changes its magnification, when distance between cross strip hinge and knife edge is varied?

a. Johansson mickrocator
b. Solex pneumatic comparator
c. Projector comparator
d. Sigma comparator
 Answer  Explanation ANSWER: Sigma comparator Explanation: No explanation is available for this question!

4)   Overall magnification of optical comparators is given as

a. (4 d / f) x ( magnification of eye piece)
b. (2 f / d) x ( magnification of eye piece)
c. (4 f / d) x ( magnification of eye piece)
d. (2 d / f) x ( magnification of eye piece)
 Answer  Explanation ANSWER: (2 f / d) x ( magnification of eye piece) Explanation: No explanation is available for this question!

5)   Which principle is used to measure distance in electronic comparator?

a. Frequency modulation
c. Both a. and b.
d. None of the above
 Answer  Explanation ANSWER: Both a. and b. Explanation: No explanation is available for this question!

6)   The sensitivity of back pressure air gauge is given by the relation shown below, what does δ R / δ p2  signify?

(δR / δt) = (δ Am / δ t) x (δ R / δ p2 )  x (δ p2  / δ Am )

a. Pneumatic sensitivity
b. Sensitivity of pressure gauge
c. Overall magnification
 Answer  Explanation ANSWER: Sensitivity of pressure gauge Explanation: No explanation is available for this question!

7)   Calculate the range of linear scale for pressure ratios between 0.6 to 0.8. The air is supplied at 5 bar to the control jet, which has a diameter of 0.45 mm and the diameter of measuring jet is 0.83 mm.
k1  = – 0.5 & k2  = 1.1

a. 0.244 mm
b. 0.0976 mm
c. 0.0244 mm
d. None of the above
 Answer  Explanation ANSWER: 0.0244 mm Explanation: No explanation is available for this question!

8)   Internal diameter of any workpiece can be measured using

a. Solex pneumatic comparator
b. Sigma comparator
c. Johansson mickrocator
d. All of the above
 Answer  Explanation ANSWER: Solex pneumatic comparator Explanation: No explanation is available for this question!

9)   Which of the following statements is true for LVDT?

a. It is a mutual capacitive transducer
b. Presence of hysteresis gives high repeatability
c. It can measure displacement and pressure
d. All of the above
 Answer  Explanation ANSWER: It can measure displacement and pressure Explanation: No explanation is available for this question!

10)   What is the phase difference, when the system is operated at excitation frequency ?

a. Phase difference is greater than 90o
b. Phase difference is less than 90o
c. Phase difference is zero
d. Unpredictable
 Answer  Explanation ANSWER: Phase difference is zero Explanation: No explanation is available for this question!