Grashoff number is given by________________?
Grashoff number is given by________________?
A. gD3.β.Δtρ2/μ2
B. gD2βΔtρ/μ2
C. gD2βΔtP2μ
D. gD3βΔtP2/μ
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For a perfectly transparent surface (like gases), the____________________?
For a perfectly transparent surface (like gases), the____________________?A. Absorptivity = 0
B. Transmissivity = 1
C. Reflectivity = 0
D. All A., B. & C.For hot feed, forward feeding as compared to backward feeding results in ______________ economy?
For hot feed, forward feeding as compared to backward feeding results in ______________ economy?A. Increased
B. Decreased
C. No effect on
D. None of theseEconomy of an evaporator is influenced by the_____________________?
Economy of an evaporator is influenced by the_____________________?A. Steam pressure
B. Feed temperature
C. Number of effect
D. Both B. & C.Overall heat transfer co-efficient for cooling of hydrocarbons by water is about_________________?
Overall heat transfer co-efficient for cooling of hydrocarbons by water is about_________________?A. 50 -100 Kcal/hr.m2.°C
B. 50 -100 W/m2.°K
C. 50 -100 BTU/hr. ft.2°F
D. 1000 – 1500 BTU/hr. ft.2°FA sphere of radius ‘R1’ is enclosed in a sphere of radius ‘R2’. The view (or shape) factor for radiative heat transfer of the outer sphere with respect to the inner sphere is ________________?
A sphere of radius ‘R1’ is enclosed in a sphere of radius ‘R2’. The view (or shape) factor for radiative heat transfer of the outer sphere with respect to the inner sphere is ________________?A. 0
B. R2/(R1+R2)
C. 1
D. (R1/R2)2Overall heat transfer co-efficient of a particular tube is U1. If the same tube with some dirt deposited on either side has coefficient U2, then_________________?
Overall heat transfer co-efficient of a particular tube is U1. If the same tube with some dirt deposited on either side has coefficient U2, then_________________?A. U1 = U2
B. U2 > U1
C. U1 > U2
D. U1 = dirt factor – U2