4.For Tutor Adil B Only! For Tutor Adil B Only! For Tutor Adil B Only! For Tutor Adil B Only! For Tutor Adil B Only!
7.Photon has mass or not? I am confused, since we say, it has zero rest mass but how does it is affected by gravity then?
Quantitative relations between transfer processes deal with the transfer of heat and mass across two bodies. The transfer of heat and mass is driven by the non-equilibrium thermal state of bodies. It involves the generation, use, conversion, and exchange of thermal energy between physical systems through various mechanisms such as conduction, convection, and radiation.
Question 1: Which of the following occur during the mass transfer?
a) Difference in concentration b) Difference in pressure
c) Difference in temperature d) Difference in chemical potential
Answer: d) Difference in chemical potential
Explanation: Mass transfer occurs to achieve equilibrium or to minimize the energy of the system. Mass transfer can occur even if there is no difference in concentration, pressure, and temperature.
Question 2: ____________ velocity is used to calculate the mass average velocity of the mixture.
a) Bulk b) Mean
c) Instantaneous d) None of these
Answer: b) Mean
Explanation: Mean velocity is used to calculate the mass average velocity of the mixture.
Question 3: ______________ forms the connecting link between the velocity and temperature profiles.
a) Biot number b) Prandtl number
c) Stanton number d) Fourier number
Answer: b) Prandtl number
Explanation: The temperature and velocity profile becomes identical when the Prandtl number is equal to one.
Question 4: Which number forms the connecting link between the temperature and concentration profiles?
a) Prandtl number b) Schmidt number
c) Fourier number d) Lewis number
Answer: d) Lewis number
Explanation: The temperature and concentration profile are identical when lewis’s number is equal to unity.
Question 5: Which one of the following has the highest emissivity?
a) Aluminium b) Polished copper
c) Tarnished copper d) Marble
Answer: c) Tarnished copper
Explanation: The emissivity of tarnished copper is 0.75 while that of polished aluminum, aluminum foil, and copper are 0.03, 0.05, and 0.03 respectively.
Question 6: The concentration of the two phases in a closed system at the interphase _____________.
a) continuously changes b) never changes
c) becomes zero d) increases
Answer: b) never changes
Explanation: The concentration changes only if the component of the two phases is added or removed. Generally, Interphase occurs at equilibrium. Once the additional component is added to a system at equilibrium, the concentration changes until it becomes uniform but differs from the previous.
Question 7: In steady-state conditions, concentration at any point never ________.
a) becomes zero b) decreases
c) increases d) changes
Answer: d) changes
Explanation: Generally, the net transfer remains the same at a steady-state condition as the concentration will be the same at every point.
Question 8: According to Lewis and Whitman theory, the departure from concentration equilibrium at the Interphase is due to __________
a) low mass transfer rates b) high mass transfer rates
c) moderate mass transfer rate d) None of these
Answer: b) high mass transfer rates
Explanation: Theoretically proved by Lewis and Whitman, that if the mass transfer rates are higher the concentration deviates from equilibrium.
Question 9: The equilibrium concentrations in the gas and the liquid phases, in mole fraction, give rise to a curve known as
a) Differential distribution curve
b) Differential concentration curve
c) Equilibrium distribution curve
d) Equilibrium concentration curve
Answer: c) Equilibrium distribution curve
Explanation: The equilibrium distribution curve represents the phase-phase equilibrium curve with the coordinates of mole fractions in both phases.
Question 10: The operation where enthalpy remains constant throughout the initial and final condition is ___________.
a) adiabatic b) isothermal
c) non-adiabatic d) non-isothermal
Answer: a) adiabatic
Explanation: In an adiabatic condition, there is no addition or removal of heat. Therefore, the enthalpy remains constant.