Chemical Heat Transfer MCQs

Option A: Coated

Option B: Oily

Option C: Glazed & polished

Option D: Smooth

Correct Answer: Oily ✔

Option A: 0.35

Option B: 0.45

Option C: 0.55

Option D: 0.85

Correct Answer: 0.45 ✔

Option A: K/h0

Option B: 2K/h0

Option C: h0/K

Option D: h0/2K

Correct Answer: K/h0 ✔

Option A: Same velocity profile or equal eddy diffusivities

Option B: Thermal or pressure mass diffusion

Option C: Viscous heating or chemical reaction

Option D: Both B. and C.

Correct Answer: D. Both B. and C. ✔

Option A: 4000

Option B: 9000

Option C: 4600

Option D: 3000

Correct Answer: 4000 ✔

Option A: There is no internal heat generation

Option B: Boundary surfaces are isothermal

Option C: Material is anisotropic

Option D: Constant temperature gradient exists

Correct Answer: Material is anisotropic ✔

Option A: Increasing temperature

Option B: Decreasing temperature

Option C: Decreasing Reynolds number

Option D: None of these

Correct Answer: Increasing temperature ✔

Option A: Increase the steam economy & decrease the capacity

Option B: Increase the steam economy & the capacity

Option C: Decrease the steam economy & the capacity

Option D: Decrease the steam economy & increase the capacity

Correct Answer: Increase the steam economy & the capacity ✔

Option A: Graetz number

Option B: Eckert number

Option C: Grashoff number

Option D: Bond number

Correct Answer: Grashoff number ✔

Option A: Parallel

Option B: Counter

Option C: Cross

Option D: None of these

Correct Answer: Cross ✔

Option A: Decreased capacity

Option B: Increase in liquor film co-efficient

Option C: Decreased effect of hydrostatic head

Option D: Increased true temperature drop

Correct Answer: Decreased capacity ✔

Option A: D/5 and D

Option B: D/2 and 2 D

Option C: D/4 and 2 D

Option D: D and 2 D

Correct Answer: D/5 and D ✔

Option A: When heat transfer area required is very high

Option B: When heat transfer area required is very low, i.e. (100-200 ft2).

Option C: Because it occupies less floor area

Option D: Because it is less costly

Correct Answer: When heat transfer area required is very low, i.e. (100-200 ft2). ✔

Option A: Zero

Option B: Unity

Option C: Same for all wavelengths

Option D: Different for all wavelengths

Correct Answer: Same for all wavelengths ✔

Option A: 0

Option B: 1

Option C: > 1

Option D: Between 0 and 1

Correct Answer: 0 ✔

Option A: Rate of heat transfer

Option B: Degree of turbulence

Option C: Degree of super-saturation

Option D: All A., B. and C

Correct Answer: D. All A., B. and C ✔

Option A: Film

Option B: Sub-cooled

Option C: Saturated nucleate

Option D: None of these

Correct Answer: Film ✔

Option A: Single effect evaporator

Option B: Single effect evaporator followed by a crystalliser

Option C: Multiple effect evaporator

Option D: Multiple effect evaporators followed by a crystalliser

Correct Answer: Multiple effect evaporator ✔

Option A: CP. μ/k

Option B: hD/k

Option C: h. CP/μ

Option D: CP. μ/h

Correct Answer: hD/k ✔

Option A: Geometric mean temperature difference

Option B: Arithmetic mean temperature difference

Option C: Logarithmic mean temperature difference

Option D: The difference of average bulk temperatures of hot and cold fluids

Correct Answer: Logarithmic mean temperature difference ✔

Option A: Increased economy

Option B: Decreased economy

Option C: Lower capacity

Option D: No effect on economy

Correct Answer: Increased economy ✔

Option A: 32

Option B: 37

Option C: 45

Option D: 50

Correct Answer: 32 ✔

Option A: mCp/kL

Option B: kL/mCp

Option C: mCp/kμ

Option D: kμ/mCp

Correct Answer: mCp/kL ✔

Option A: Nst α f

Option B: Nst α NRe

Option C: NNu α f

Option D: NRe α f

Correct Answer: Nst α f ✔

Option A: Nitrogen

Option B: Steel

Option C: Carbon black

Option D: Tar

Correct Answer: Nitrogen ✔

Option A: Absorptivity = 1

Option B: Reflectivity = 1

Option C: Emissivity = 0

Option D: Transmissivity = 1

Correct Answer: Absorptivity = 1 ✔

Option A: High pressure

Option B: Vacuum

Option C: Backward feed

Option D: None of these

Correct Answer: Vacuum ✔

Option A: Condensation of the saturated vapor on a cold surface

Option B: Concentration of a corrosive solution by evaporation

Option C: Heat transfer between two highly viscous liquids

Option D: Boiling of a liquid on a hot surface

Correct Answer: Boiling of a liquid on a hot surface ✔

Option A: Dowtherm

Option B: Mercury

Option C: Liquid metal (e.g. molten sodium)

Option D: Fused salts (e.g., an eutectic mixture of 53% KNO3, 40% NaNO2and 7% NaNO3)

Correct Answer: Mercury ✔

Option A: 20.8

Option B: 40.8

Option C: 40.4

Option D: 20.4

Correct Answer: 40.8 ✔

Option A: Through a metallic wall

Option B: By direct contact of hot flue gas with air

Option C: By heating an intermediate material (like chequor bricks) and then heating the air from this

Option D: None of these

Correct Answer: C. By heating an intermediate material (like chequor bricks) and then heating the air from this
hot material ✔

Option A: 6000

Option B: 24000

Option C: 60000

Option D: 48000

Correct Answer: 24000 ✔

Option A: 1.66

Option B: 88.66

Option C: 3.66

Option D: Dependent on NRe only

Correct Answer: 3.66 ✔

Option A: Corrosiveness

Option B: Fouling characteristic

Option C: Viscosity

Option D: None of these

Correct Answer: None of these ✔

Option A: 1

Option B: 0

Option C: 0.78

Option D: 0.95

Correct Answer: 1 ✔

Option A: Boiling point elevations

Option B: Temperature of the feed

Option C: Rate of heat transfer

Option D: Ratio of the weight of the thin liquor to thick liquor

Correct Answer: Boiling point elevations ✔

Option A: Exit-fluid temperature > wall temperature

Option B: Exit fluid temperature < wall temperature

Option C: Exit fluid temperature = wall temperature

Option D: Graetz number > 100

Correct Answer: Exit fluid temperature = wall temperature ✔

Option A: High vacuum in the evaporator

Option B: High evaporation rate

Option C: Foaming of the solution

Option D: High heat transfer rate

Correct Answer: Foaming of the solution ✔

Option A: Provide very large heat transfer co-efficient

Option B: Results in making part of the heating surface inactive

Option C: Results in abruptly increased velocity

Option D: None of these

Correct Answer: Results in making part of the heating surface inactive ✔

Option A: LMTD is greater

Option B: Less surface area is required for a given heat transfer rate

Option C: Both A. and B.

Option D: More surface area is required for a given heat transfer rate

Correct Answer: C. Both A. and B. ✔

Option A: Conduction

Option B: Natural convection

Option C: Forced convection

Option D: None of these

Correct Answer: Natural convection ✔

Option A: 1

Option B: < 1

Option C: > 1

Option D: None of these

Correct Answer: 1 ✔

Option A: Heat exchanger

Option B: Condenser

Option C: Multiple effect evaporator

Option D: Steam jacketed kettle

Correct Answer: Steam jacketed kettle ✔

Option A: < 1

Option B: > 1

Option C: 1

Option D: ∞

Correct Answer: < 1 ✔

Option A: Dense structure

Option B: High proportion of air space

Option C: High specific heat

Option D: None of these

Correct Answer: High proportion of air space ✔

Option A: Dense structure

Option B: High proportion of air space

Option C: High specific heat

Option D: None of these

Correct Answer: High proportion of air space ✔

Option A: Capacity of the evaporator is decreased

Option B: Capacity of the evaporator is increased

Option C: True temperature drop increases

Option D: Both B. and C.

Correct Answer: Capacity of the evaporator is decreased ✔

Option A: Heating volume

Option B: Heat transfer area

Option C: Nusselt number

Option D: None of these

Correct Answer: Heat transfer area ✔

Option A: k/ρCp

Option B: ρCp/k

Option C: μCp/a

Option D: μ/hCp

Correct Answer: k/ρCp ✔

Option A: Least at the inlet of the first effect

Option B: Least at the outlet of the last effect

Option C: Highest at the inlet of the last effect

Option D: Highest at the outlet of the last effect

Correct Answer: Least at the outlet of the last effect ✔

Option A: Aluminium foil

Option B: Coal dust

Option C: Refractory bricks

Option D: Iron plates

Correct Answer: Aluminium foil ✔

Option A: Fourier’s law

Option B: Newton’s law of cooling

Option C: Fick’s law

Option D: None of these

Correct Answer: B. Newton’s law of cooling ✔

Option A: Always less than h1

Option B: Always between h1 and h2

Option C: Always higher than h2

Option D: Dependent on metal resistance

Correct Answer: Always between h1 and h2 ✔

Option A: Flows through the tube

Option B: Flows outside the tubes

Option C: Can flow either inside or outside the tubes

Option D: Should not be used as it gives very high pressure drop

Correct Answer: Flows outside the tubes ✔

Option A: r = 2k/h

Option B: r = k/h

Option C: r = k/2h

Option D: r = h/k

Correct Answer: r = k/h ✔

Option A: Concentrations

Option B: Chemical potentials

Option C: Activity co-efficients

Option D: Mass transfer co-efficients

Correct Answer: Concentrations ✔

Option A: Greater than that for un-insulated steam pipe

Option B: Less than that of the un-insulated steam pipe

Option C: Equal to that of the un-insulated steam pipe

Option D: Less than the steam pipe with 5 cms insulation

Correct Answer: Less than that of the un-insulated steam pipe ✔

Option A: Economiser

Option B: Regenerator

Option C: Ceramic recuperator

Option D: None of these

Correct Answer: None of these ✔

Option A: Velocity of circulation

Option B: Liquor-film co-efficient

Option C: Both A. and B.

Option D: Neither A. and B.

Correct Answer: D. Neither A. and B. ✔

Option A: (ΔT)2

Option B: (ΔT)4

Option C: (ΔT)3

Option D: √(ΔT)

Correct Answer: (ΔT)3 ✔

Option A: Reduce the capacity

Option B: Reduce the economy

Option C: Increase the economy

Option D: None of these

Correct Answer: Reduce the capacity ✔

Option A: Oily

Option B: Coated

Option C: Clean & smooth

Option D: Dirty

Correct Answer: Clean & smooth ✔

Option A: Nusselt

Option B: Leidenfrost

Option C: Boiling

Option D: Burnout

Correct Answer: Leidenfrost ✔

Option A: Nucleate

Option B: Pool

Option C: Low pressure

Option D: None of these

Correct Answer: Pool ✔

Option A: Prandtl

Option B: Reynolds

Option C: Both A. & B.

Option D: Neither A. nor B.

Correct Answer: Reynolds ✔

Option A: Steam ejector

Option B: Entrainment separator

Option C: Compressor

Option D: Vacuum pump

Correct Answer: Entrainment separator ✔

Option A: 3

Option B: 0.33

Option C: 1

Option D: 1.33

Correct Answer: 1 ✔

Option A: Internally

Option B: Externally

Option C: Both A. and A.

Option D: Neither A. nor B.

Correct Answer: Internally ✔

Option A: 2f

Option B: f

Option C: f/2

Option D: f/4

Correct Answer: f ✔

Option A: αT

Option B: α × 1/T

Option C: α T4

Option D: Independent of T

Correct Answer: α × 1/T ✔

Option A: More

Option B: Less

Option C: Same

Option D: Unpredictable

Correct Answer: Less ✔

Option A: Total heat transfer area of all the effects is -less than that in a single effect evaporator system

Option B: Total amount of vapor produced per Kg of feed steam in a multiple effect system is much

Option C: Boiling point elevation in a single effect system is much higher than that in any effect in a

Option D: Heat transfer co-efficient in a single effect is much lower than that in any effect in a multieffect

Correct Answer: B. Total amount of vapor produced per Kg of feed steam in a multiple effect system is much
higher than in a single effect ✔

Option A: ∞

Option B: 0

Option C: Equal to the difference between hot and cold fluids inlet temperature

Option D: Equal to the difference between hot fluid inlet temperature and cold fluid outlet temperature

Correct Answer: 0 ✔

Option A: Viscous

Option B: Elastic

Option C: Inertial

Option D: None of these

Correct Answer: Viscous ✔

Option A: Hyperbolic

Option B: Parabolic

Option C: Linear

Option D: Logarithmic

Correct Answer: Linear ✔

Option A: Open pan

Option B: Long tube

Option C: Agitated film

Option D: None of these

Correct Answer: Agitated film ✔

Option A: 1/V̅ -0.8

Option B: V̅ -0.8

Option C: V̅ -2

Option D: 1/ V̅ -2

Correct Answer: 1/V̅ -0.8 ✔

Option A: Increase very rapidly

Option B: Increase slowly

Option C: Decrease slowly

Option D: Remain unaffected

Correct Answer: Increase slowly ✔

Option A: Saturated

Option B: Supersaturated

Option C: Under-saturated

Option D: All A., B. and C.

Correct Answer: B. Supersaturate ✔

Option A: At high fluid velocity

Option B: At low velocity

Option C: When fluid flows past a smooth surface

Option D: None of these

Correct Answer: At high fluid velocity ✔

Option A: Higher condensing film co-efficient is desired

Option B: Condensate is corrosive in nature

Option C: Lower pressure drop through the exchanger is desired

Option D: Temperature of the incoming vapor is very high

Correct Answer: Condensate is corrosive in nature ✔

Option A: Cube

Option B: Plate

Option C: Sphere

Option D: All will cool at the same rate

Correct Answer: Sphere ✔

Option A: 5 minutes

Option B: 10 minutes

Option C: 20 minutes

Option D: 40 minutes

Correct Answer: 5 minutes ✔

Option A: Increases the rate of condensation

Option B: Decreases thermal resistance

Option C: Is desirable to increase the film co-efficient

Option D: None of these

Correct Answer: None of these ✔

Option A: K/h0

Option B: 2K/h0

Option C: hi/K

Option D: 2hi/K

Correct Answer: K/h0 ✔

Option A: Counter flow with process stream on shell side

Option B: Counter flow with process stream on tube side

Option C: Parallel flow with process stream on shell side

Option D: Parallel flow with process stream on tube side

Correct Answer: Counter flow with process stream on shell side ✔

Option A: Grashoff number

Option B: Peclet number

Option C: Reynolds number

Option D: Prandtl number

Correct Answer: Grashoff number ✔

Option A: BTU/hr. ft2°F

Option B: BTU/hr. °F. ft

Option C: BTU/hr. °F

Option D: BTU/hr. ft

Correct Answer: BTU/hr. ft2°F ✔

Option A: 40.5

Option B: 34.4

Option C: 26.8

Option D: 25

Correct Answer: 34.4 ✔

Option A: P and Q

Option B: P and R

Option C: P and S

Option D: R and S

Correct Answer: P and S ✔

Option A: Finned tube heat exchanger with air inside and steam outside

Option B: Finned tube heat exchanger with air outside and steam inside

Option C: Shell and tube heat exchanger with air inside tubes and steam on shell side

Option D: Shell and tube heat exchanger with air on shell side and steam inside tubes

Correct Answer: Finned tube heat exchanger with air outside and steam inside ✔

Option A: Plain carbon steel

Option B: Stainless steel

Option C: Lead

Option D: Copper

Correct Answer: Lead ✔

Option A: W/m.k

Option B: W/m

Option C: W/m.k2

Option D: None, ‘a’ is just a number

Correct Answer: W/m.k ✔

Option A: 0.001 to 1

Option B: 0.6 to 120

Option C: 0.5 to 5

Option D: 120 to 400

Correct Answer: 0.6 to 120 ✔

Option A: 0.06 to 120

Option B: 0.6 to 120

Option C: 1 to 103

Option D: 1 to 50

Correct Answer: 0.6 to 120 ✔

Option A: (COP)R = (COP)HP = 0.6

Option B: (COP)R = 2.5; (COP)HP = 1.5

Option C: (COP)R = 1.5; (COP)HP = 2.5

Option D: (COP)R = (COP)HP = 2.5

Correct Answer: (COP)R = 1.5; (COP)HP = 2.5 ✔

Option A: Thermal conductivity

Option B: Heat flux

Option C: Heat transfer co-efficient

Option D: Thermal diffusivity

Correct Answer: Heat flux ✔

Option A: Sum

Option B: Difference

Option C: Ratio

Option D: None of these

Correct Answer: Sum ✔

Option A: Small

Option B: Large

Option C: All

Option D: One fixed

Correct Answer: All ✔

Option A: Decreases

Option B: Increases

Option C: Remain constant

Option D: First decreases upto certain temperature and then increases

Correct Answer: Increases ✔