## MCQs

Total Questions : 69 | Page 1 of 7 pages
Question 1. Ratio of actual velocity to sonic velocity is known as
1.    Mach number
2.    Peclet number
3.    Reynolds number
4.    Grashof number
Answer: Option A. -> Mach number
Answer: (a).Mach number
Question 2. Let us say Mach number (greater than one), the flow is
1.    Sonic
2.    Subsonic
3.    Supersonic
4.    No flow
Answer: Option C. -> Supersonic
Answer: (c).Supersonic
Question 3. Free convection heat flow does not depends on
1.    Density
2.    Coefficient of viscosity
3.    Gravitational force
4.    Velocity
Answer: Option B. -> Coefficient of viscosity
Answer: (b).Coefficient of viscosity
Question 4. The value of Prandtl number for air is about
1.    0.1
2.    0.4
3.    0.7
4.    1.1
Answer: Option C. -> 0.7
Answer: (c).0.7
Question 5. Which dimensionless number has a significant role in forced convection?
1.    Prandtl number
2.    Peclet number
3.    Mach number
4.    Reynolds number
Answer: Option D. -> Reynolds number
Answer: (d).Reynolds number
Question 6. The non-dimensional parameter known as Stanton number is used in
1.    Forced convection heat transfer
2.    Condensation heat transfer
3.    Natural convection heat transfer
4.    Unsteady state heat transfer
Answer: Option A. -> Forced convection heat transfer
Answer: (a).Forced convection heat transfer
Question 7. Heat is loss from a 100 mm diameter steam pipe placed horizontally in ambient air at 30 degree Celsius. If the Nusselt number is 25 W/m² K and thermal conductivity of the air is 0.03 W/m K, then heat transfer coefficient will be
1.    7.5 W/m² K
2.    16.5 W/m² K
3.    25 W/m² K
4.    30 W/m² K
Answer: Option A. -> 7.5 W/m² K
Answer: (a).7.5 W/m² K
Question 8. The Prandtl number will be lowest for
1.    Water
2.    Liquid metal
3.    Lube oil
4.    Aqueous solution
Answer: Option B. -> Liquid metal
Answer: (b).Liquid metal
Question 9. The dimensionless parameter l³ p² β g d t/µ² is referred to as
1.    Stanton number
2.    Schmidt number
3.    Grashof number
4.    Peclet number
Answer: Option C. -> Grashof number
Answer: (c).Grashof number
Question 10. Ratio of inertia force to viscous force is known as
1.    Grashof number
2.    Reynolds number
3.    Peclet number
4.    Stanton number
Answer: Option B. -> Reynolds number
Answer: (b).Reynolds number