PrepBharat

1. The equation of motion for the liquid film in fully developed laminar flow in y-direction is:
a) µd²u_y/dx² + ρg =0
b) µd²u_y/dy² + ρg =0
c) µd²u_y/dz² + ρg =0
d) µd²u_y/dx² = 0

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2. Which two forces is the reynold’s number a ratio of?
a) Gravitational force and interfacial force
b) Interfacial force and viscous force
c) Thermal conductivity and electrical conductivity
d) Conduction and convection

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3. What value of Reynold’s number is obtained with water?
a) 8
b) 16
c) 25
d) 50

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4. What value of reynold’s number represents a laminar flow?
a) 3
b) 2500
c) 5000
d) 78

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5. Which of the following is correct about Reynold’s number?
a) 3less thanN_reless than1200
b) 3less thanreless than1600
c) 25less thanreless than1200
d) 8less thanreless than1200

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6. Prandtl’s number is the ratio of which two quantities?
a) Momentum conductivity and thermal conductivity
b) Coefficient of convection to thermal conductivity
c) Momentum diffusivity and thermal diffusivity
d) Interfacial force and viscous force

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7. Which of the following is true about prandtl’s number?
a) N_pr = C_pµ/k
b) N_pr = C_pk/µ
c) N_pr = C_vµ/k
d) N_pr = C_pµ

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8. What is the physical significance of nusselt’s number?
a) Ratio of convective heat transfer to conductive heat transfer
b) Ratio of convective heat transfer to conductive heat transfer
c) Ratio of total heat transfer to conductive heat transfer
d) Ratio of total transfer to convective heat transfer

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9. What is the correct formula for nusselt’s number?
a) hµ/k
b) hρ/k
c) hL/k
d) hΔTL/k

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10. Which of the following is most true?
a) N_a = kcA(c_ai – c_a)
b) N_a = kcAΔc
c) N_a = kcA(c_ai – c_a)_mean
d) N_a = kcA(c_ai – c_a)_{log mean}

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