Quiz: Mechanical Engineering
Exam: UPSSSC JE
Each question carries 1 mark
Negative marking: 1/4 mark
Time: 10 Minutes
Q1. An adiabatic process in a thermodynamic system is one in which there is______
(a) Limited heat transfer to or from the system through the boundary
(b) No heat transfer to or from the system through the boundary
(c) No internal energy changes
(d) No energy transfer to or from the system through the boundary
Q2. The difference between the actual temperature of the superheated steam and
saturation temperature corresponding to its pressure is known as
(a) Degree of saturation
(b) Degree of superheat
(c) Dryness fraction
(d) None of these
Q3. The type of coupling used to join two shafts whose axes are neither in same straight line
nor parallel but intersect is called
(a) Flexible coupling
(b) Universal coupling
(c) Chain coupling
(d) Oldham’s coupling
Q4. Which of the following is an extensive property?
(c) Specific entropy
Q5. For which of the following gas internal energy and enthalpy are the function of
(a) Any gas
(c) perfect gas
(d) saturated vapor
Q6. According to kinetic theory of gases, the absolute zero temperature is attained when
(a) Volume of gas becomes zero
(b) Pressure of gas becomes zero
(c) Mass of gas becomes zero
(d) Kinetic energy of gas molecules becomes zero
Q7. Spring stiffness is
(a) Ratio of coil diameter to wire diameter
(b) Load required to produce unit deflection
(c) Its ability to absorb shock
(d) Its capability to store energy
Q8. A screw is specified by
(a) Major diameter X pitch
(b) Minor diameter X pitch
(c) Minor diameter X length
(d) Mean diameter X pitch
Q9. Kelvin-Planck statement is applicable for
(a) Heat Pump
(c) Heat engine
(d) None of these
Q10. When wet steam undergoes adiabatic expansion
(a) Its dryness fraction increases
(b) Its dryness fraction decreases
(c) Its dryness fraction may increase or decrease
(d) Its dryness fraction remains constant
S1. Ans (b)
Sol. For an adiabatic process, there is no heat transfer to or from the system through the boundary.
Sol. Difference between saturated steam temperature and superheated steam temperature
at same pressure is known as degree of superheat.
Sol. Universal coupling or Hook’s joint is used to connect to non-parallel or intersecting
S4. Ans (a)
Sol. Extensive properties are those properties which depend on mass of the system. E.g. Volume, mass, entropy etc.
S5. Ans (c)
Sol. Internal Energy and enthalpy are the function of temperature only for perfect gases.
Sol. We know that
Kinetic Energy of gases (K.E.)=3/2(kT)
Where, k=Boltzmann’s constant
and T=absolute temperature of gas.
When, T=0 then K.E.=0
Sol. Spring stiffness (k)=(Load (W))/(Deflection(∆))
Sol. A screw is specified by its major diameter and pitch.
Sol. Kelvin-Planck’s statement is valid for heat engine.
Sol. During adiabatic expansion of wet steam, dryness fraction may decrease due to cooling
or it may increase due to friction.