Thermodynamics-SSC JE Mechanical Engineering Practice Questions
Thermodynamics questions for practice for SSC JE Mechanical Engineering exam. The answers for the questions have been shared below, in case of any doubt or query, feel free to leave a comment in the comment box below.
Q1) According to Gay Lussac law for a perfect gas, the absolute pressure of a given mass varies directly as
- Absolute temperature
- Absolute temperature, if volume is kept constant
- volume, if temperature is kept constant
Q2) Temperature of a gas is produced due to
- its heating value
- kinetic energy of molecules
- repulsion of molecules
- attraction of molecules
Q3) The pressure of a gas in terms of its mean kinetic energy per unit volume E is equal to
Q4) In order that a cycle be reversible, following must be satisfied
- free expansion or friction resisted expansion/compression process should not be encountered
- when heat is being absorbed, temperature of hot source and working substance should be same
- when heat is being rejected, temperature of cold source and working substance should be same
- all options are correct
Q5) The property of a working substance, which increases or decreases according to the heat supplied or removed in a reversible manner, is called _____.
- none of these
Q6) Non quasistatic process is ____.
- free expansion of gas
- expansion of a gas in a cylinder under constant pressure
- rapid compression of a gas in a cylinder
- gradual compression of a gas in a cylinder
Q7) If a gas vapor is allowed to expand through a very minute aperture, then such a process is known as ____.
- free expansion
- hyperbolic expansion
- parabolic expansion
Q8) Entropy change depends on ____.
- heat transfer
- mass transfer
- change of temperature
- thermodynamic state
Q9) An engine working between positive temperatures _____.
- can be a heat pump
- cannot be a heat pump
- must be a heat pump
- can be a heat pump if frictionless machine is used
Q10) Superheated vapor behaves ______.
- exactly as gas
- as steam
- as ordinary vapor
- approximately as gas
Q11) When a gas flows through a very long pipe of uniform cross section, the flow is approximately
Q12) A football was inflated to a gauge pressure of 1 bar when the ambient temperature was . When the game started next day, the air temperature at the stadium was . Assume that the volume of the football remains constant at 2500 cc. Gauge pressure of air to which the ball must have been originally inflated so that it would equal 1 bar gauge at the stadium is ____.
- 2.23 bar
- 1.94 bar
- 1.07 bar
- 1 bar
Q13) The valves mounted on the boilers which change the direction of flow of steam by and valves fitted in the pipelines which allow the steam in the same direction are respectively called as ______.
- stop valves and junction valves
- junction valves and stop valves
- junction valves and safety valves
- feed safety valves and stop valves
Q14) In a cross compound steam engine ______.
- one high and one low pressure cylinders are set side by side, driving the same shaft, cranks being set apart
- two cylinders are centred on the same piston rod, the 1.p cylinder being placed nearest the crankshaft
- two cylinders are set at , usually to save floor space
- none of these
Q15) Maximum work by an expansion of a gas in a closed system is possible when process takes place at constant
Q16) Which of the following represents the perpetual motion machine of the first kind
- engine with 100% thermal efficiency
- a full reversible engine
- transfer of heat energy from low temperature source to high temperature source
- a machine that continuously creates its own energy
Q17) When a process undergoes a complete cycle then the change of entropy will be
- +ve or -ve depending on initial condition
Q18) When a liquid boils at constant pressure, the following parameter increases
- heat of vaporization
- kinetic energy
Q19) it is proposed to make a direct heat-to-work transfer converter out of an elementary system which absorbs heat while doing isothermal work exactly equal to
- not possible
- not desirable
Q20) When two gases suddenly mix up with each other then resultant entropy of the system will
- remain same
- may increase or decrease depending upon the initial conditions of the gases