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1338. If Prandtl number is greater than the Schmidt number, then the

Thermal boundary layer lies inside the concentration boundary layer

Concentration boundary layer lies inside the thermal boundary layer

Thermal & concentration boundary layers are of equal thickness

Hydrodynamic(i.e., momentum)boundary layer is thicker than the other two

✅ The correct answer is option A.

1301. Temperature profile in steady state heat transfer is

Asymptotic

Hyperbolic

Parabolic

Linear

✅ The correct answer is option D.

1304. Thermal diffusivity is the most important in heat transfer by

Conduction

Radiation

Condensation

Natural convection

✅ The correct answer is option A.

1307. The Graetz number is concerned with the

Mass transfer between a gas and a liquid

Absorption with chemical reaction

Heat transfer in turbulent flow

Heat transfer in laminar flow

✅ The correct answer is option D.

1310. The Sieder-Tate correlation for heat transfer in turbulent flow in pipe gives Nu α Re0.8, where, Nu is the Nusselt number and Re is the Reynolds number for the flow. Assuming that this relation is valid, the heat transfer co-efficient varies with the pipe diameter (D) as

(D)-1.8

(D)-0.2

(D)0.2

(D)1.8

✅ The correct answer is option B.

1313. For specified tube outside diameter, higher BWG means higher

Tube thickness

Cross-sectional area

Weight per unit length

None of these

✅ The correct answer is option B.

1316. Fruit juice (a heat sensitive material) can be concentrated in a __________ evaporator.

Long tube

Falling film

High pressure

None of these

✅ The correct answer is option B.

1319. 1000 kg of wet solids are to be dried from 60% to 20% moisture (by weight). The mass of moisture removed in kg is

520

200

400

500

✅ The correct answer is option C.

1322. Natural convection is characterised by

Grashhoff number

Peclet number

Reynolds number

Prandtl number

✅ The correct answer is option A.

1325. In a shell and tube heat exchanger, square pitch compared to triangular pitch

Gives a higher shell side pressure drop

Gives a lower shell side pressure drop

Can pack more surface area into a shell of given diameter

None of these

✅ The correct answer is option A.

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