The efficiency of cycle would be
A.100 percent
B.88.8 percent
C.78.3 percent
D.66.7 percent
E.37.7 percent
Category: Thermodynamics Mcqs
The triple point for carbondioxide is at about -56.7 C and about 5 atm, pressure. It means that
A.When solid CO2 is exposed to 1 atm pressure it begins to change directly to gas
B.When CO2 is exposed to a below 5 atmosphere pressure only solid and liquid phase exist together
C.Below 57.7 C CO2 exists only in liquid form
D.Above 56.7 C CO2 exists only as a liquid
E.Mass transfer at triple point is maximum
An open system
A.Is a specified region where transfers of energy and/or mass take place
B.Is a region of constant mass and only energy is allowed to cross the boundaries
C.Cannot transfer either energy or mass to or from the surroundings
D.Has a mass transfer across its boundaries, and the mass within the system is not necessarily constant
E.None of the above
The rate of radiant energy, which is emitted by a surface at any temperature and in small wavelengths is found from the known rate of energy, which under the same conditions would be emitted from a black surface, by multiplying with the absorptivity. Above enunciation is known as
A.Planck’s law
B.Kirchhoff’s law
C.Stefan Bolzmann’s law
D.Lambart’s rule
E.None of the above
If the sun becomes twice as hot
A.its output of radiation energy will fall
B.it will disintegrate into fragments
C.it will radiate predominantly in infra-red
D.it will radiate predominantly ultraviolet
According to kinetic theory of heat
A.Temperature should rise during boiling
B.Temperature should fall during freezing
C.At low temperatures all bodies are in solid state
D.At absolute zero there is absolutely no vibration of molecules
The gas turbine works on
A.Rankine cycle
B.Carnot cycle
C.Otto cycle
D.Brayton cycle
E.Erricson cycle
In a Joule cycle, the heat is rejected at
A.Constant volume
B.Constant pressure
C.Constant temperature
D.Constant enthalpy
E.Constant entropy
A liquid flowing through a tube is turbulent. In which case will the maximum change in heat transfer coefficient occur?
A.Diameter of the tube is increased 2 times maintaining the velocity of flow constant
B.Diameter of the tube is increased 2 times maintaining the rate of liquid flow constant
C.Diameter of the tube is increased 4 time maintaining the ratio of liquid flow constant
D.Diameter of the tube is increased 4 times maintaining the velocity of flow constant
