< SSC JE 2017 Mechanical Engineering Paper 1st March 2017, 1 shift Solved paper

## STAY WITH US # SSC JE 2017 Mechanical Engineering Paper 1st March 2017, 1 shift Solved paper

QID 801- The ratio  surface convection resistance to internal conduction resistance is known as_______.
1) Grashoff number
2) Biot number
3) Stanton number
4) Prandtl number
QID 802 - An ideal air compressor cycle (with clearance) on p-v diagram can be represented by ________ processes.
1) One adiabatic, two isobaric, and one constant volume
2) Two adiabatic and two isobaric
3) Two adiabatic, one isobaric, and one constant volume
4) One adiabatic, one isobaric, and two constant volume
QID 803 - In a shell and tube heat exchanger, baffles are provided on the shell side to______.
1) Prevent the stagnation of shell side fluid
2) Improve heat transfer
3) Provide support for tubes
4) All options are correct
Correct Answer: All options are correct
QID 804 - The ratio of the thickness of thermal boundary layer to the thickness of hydrodynamic boundary layer is equal to (Prandtl number)n, where n is______.
1) - 1/3
2) - 2/3
3) 1
4) – 1
QID 805 - In regarding nucleate boiling _______.
1) The temperature of the surface is greater than the saturation temperature of the liquid
2) Bubbles are created by expansion of entrapped gas or vapour at small cavities in the surface
3) The temperature is greater than that of film boiling
4) All options are correct
Correct Answer: The temperature is greater than that of film boiling
QID 806 - Boundary layer is defined as ______.
1) A thin layer at the surface where gradients of both velocity and temperature are small
2) A thin layer at the surface where velocity and velocity gradients are large
3) A thick layer at the surface where velocity and temperature gradients are large
4) A thin layer at the surface where gradients of both velocity and temperature are large
Correct Answer: A thin layer at the surface where gradients of both velocity and temperature are large
QID 807 - Two insulating materials of thermal conductivity K and 2K are available for lagging a pipe carrying a hot fluid. If the radial thickness of each material is the same _____.
1) Material with higher thermal conductivity should be used for the inner layer and one with layer and one with lower thermal conductivity for the outer
2) Material with lower thermal conductivity should be used for the inner layer and one with higher thermal conductivity for the outer
3) It is immaterial in which sequence the insulating materials are used
4) None of these
Correct Answer: Material with lower thermal conductivity should be used for the inner layer and one with higher thermal conductivity for the outer
QID 808 - Critical thickness of insulation for spheres is given by _____.
1) k/h
2) k/4h
3) h/2k
4) 2k/h
QID 809 - Which surface will have the least emissivity?
1) Smooth glass
2) Plaster
3) Aluminium foil
4) Concrete
QID 810 - The process of heat transfer from one particle of the body to another without the actual motion of the particle, is known as ______ .
1) Conduction
2) Convection
4) All options are correct
QID 811 - The process of heat transfer from a hot body to a cold body in a straight line, without affecting the intervening medium, is known as ______.
1) Conduction
2) Convection
4) All options are correct
QID 812 - Heat is transferred from an electric bulb by ______.
1) Conduction
2) Convection
4) All options are correct
QID 813 - Assumption made in the Fourier's law is that the heat flow
B. Through a solid medium in one dimension
1) Only (A)
2) Only (B)
3) Both (A) and (B)
4) None of these
Correct Answer: Both (A) and (B)
QID 814 - If thermal conductivity of a material of wall varies as K0 (1 + αt), then the temperature at the centre of the wall as compared to that in case of constant thermal conductivity, will be ______.
1) More
2) Less
3) Same
4) Depend on other factors
QID 815 - With increase in temperature, thermal conductivity of air ______.
1) Increases
2) Decreases
3) Remains the same
4) None of these