Quiz:Mechanical Engineering 29 June 2020

Quiz: Mechanical Engineering
Exam: UPSSSC JE
Topic: Miscellaneous

Each question carries 1 mark
Negative marking: 1/4 mark
Time: 10 Minutes

Q1. Young’s modulus (E), Bulk modulus (K) and Shear modulus (G) are related by
(a) E=(K+G)/6K
(b) E=9KG/(3K+G)
(c) E=(9K+G)/6K
(d) E=(K+6G)/6K

Q2. Open circuit test on the transformer is to measure its
(a) Copper loss
(b) Leakage reactance
(c) Equivalent impedance
(d) Core loss

Q3. Number of minimum control points required to generate a quadratic B-spline curve
(a) 2
(b) 3
(c) 4
(d) 5

Q4. Which is a positive drive?
(a) Flat belt drive
(b) Round belt drive
(c) Crossed belt drive
(d) Timing belt

Q5. De-aerator in thermal power plants is used to
(a) Remove dissolved gases from feed water
(b) Reduce temperature of feed water
(c) Reduce pressure of feed water
(d) None of the above

Q6. When the state is being changed from gas to liquid state through the process of condensation, the temperature?
(a) increases
(b) decreases
(c) remains constant
(d) may increase or decrease

Q7. Air refrigeration system operates on
(a) Carnot cycle
(b) Rankine cycle
(c) Reversed Carnot cycle
(d) Bell Coleman cycle

Q8. High API gravity of fuel means:
(a) Lower Diesel index
(b) Lower Brake specific fuel consumption
(c) Lower heat of combustion
(d) Lower ignition quality

Q9. A refrigerant should have:
(a) High specific heat of liquid
(b) High boiling point
(c) High latent heat of vaporization
(d) Low critical temperature

Q10. Lumped heat capacity approach of transient heat conduction analysis is used:
(a) For bodies of very high conductive resistance
(b) When temperature variation throughout the body is very high
(c) When temperature variation throughout the body is very low
(d) For Biot number > 5

Solutions

S1. Ans (b)
Sol. Relation between E, K and G is
E=9KG/(3K+G)

S2. Ans (d)
Sol. The purpose of the open-circuit test is to determine the no-load current and losses of the transformer because of which their no-load parameters are determined. The core loss of the transformer can be determined by this test.

S3. Ans (b)
Sol. B-splines are a more general type of curve than Bezier curves. In a B-spline each control point is associated with a basis function. If the order of B-spline is n then we require (n+1) control points to generate B-spline. So, for quadratic B-spline, we need 3 control points.

S4. Ans (d)
Sol. As slip occurs in other given options, so these all are negative drive except timing belt.

S5. Ans (a)
Sol. De-aerator is fixed with the feed water tank of the boiler in power plants. It is used to remove dissolved gases from the water, which otherwise, causes reduction in heat transfer in the boiler and oxidation in the tubes of the boiler.

S6. Ans (c)
Sol. Temperature and pressure both remain constant in all the phase changing processes. Such as condensation, boiling, freezing etc. In the condensation process, heat of vaporization is released and vapor is converted into liquid.

S7. Ans (d)
Sol. Bell-Coleman cycle is an air refrigeration cycle. It uses air as refrigerant and this cycle is majorly used in aircrafts due to low weight per ton of refrigeration.

S8. Ans (b)
Sol. API stands for American Petroleum institute. API gravity is a measure of how heavy or light a petroleum liquid is as compared to water. High API gravity of fuel represents lower brake specific fuel consumption.

S9. Ans (c)
Sol. There are following properties of a good refrigerant:
1.Low boiling point.
2.Low freezing point
3.High latent heat of vaporization
4.Low viscosity
5.Low specific volume
6.High critical temperature

S10. Ans (c)
Sol. Lumped heat capacity approach of transient heat conduction analysis is used when conductive resistance of the body is negligible and hence, the variation in temperature throughout the body is also negligible.

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