# Multiple choice question for engineering

## Set 1

1. Which of the followings is a wrong statement?

The shape factor is equal to one

a) For any surface completely enclosed by another surface

b) For infinite parallel planes radiating only to each other

c) For a flat or convex surface with respect to itself

d) Inside cylinder to outer cylinder of a long co-axial cylinder

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2. Establish a relation for the shape factor of cylindrical cavity with respect to itself of depth h and diameter d. The cavity is closed on its outer surface with a flat plate

a) 4 h/4 h + d

b) 4 h + d/h

c) 4 h + d/4 h

d) h/4 h + d

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_{11}+ F

_{ 12}= 1 and F

_{21}+ F

_{ 22}= 1. But F

_{ 22}= 0, so F

_{11}= 1 – A

_{2 }/ A

_{1}.

3. The reciprocity theorem states that

a) F _{12} = F _{21}

b) A _{1 }F _{12 }= A_{ 2} F _{21}

c) A _{1 }F _{21 }= A_{ 2} F _{12}

d) A _{2 }F _{21 }= A_{ 1} F _{12}

Where symbols have their usual meanings

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4. Two radiating surface A _{1} = 6 m^{2} and A _{2} = 4 m^{2} have shape factor F _{12} = 0.1. Then the shape factor F _{21} will be

a) 0.12

b) 0.18

c) 0.15

d) 0.10

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_{1 }F

_{12 }= A

_{ 2}F

_{21}.

5. What is the value of shape factor for two infinite parallel surfaces separated by a distance x?

a) 0

b) 1

c) x

d) Infinity

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6. What is the shape factor of a sphere of diameter d inside a cubical box of length l = d?

a) π/6

b) 2 π/6

c) π/3

d) π/4

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_{11}+ F

_{ 12}= 1 or F

_{12}= 1. So, F

_{21 }= π/6.

7. What is the shape factor of hemispherical surface closed by a plane surface of diameter d?

a) 0

b) 1.5

c) 1

d) 0.5

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_{11}+ F

_{ 12}= 1 and F

_{21}= 1. Therefore, F

_{11}= 0.5.

8. Establish a relation for shape factor for a conical cavity with respect to itself of depth h and diameter d. The cavity is closed on its outer surface with a flat plate

a) 1 – d/ (4 h ^{2} + d) ^{1/2}

b) 1 – d/ (4 h ^{2} + d ^{2}) ^{1/2}

c) 1 – d/ (4 h + d ^{2}) ^{1/2}

d) 1 – d/ (h ^{2} + d ^{2}) ^{1/2}

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_{11}= 1 – A

_{2 }/ A

_{1}= 1 – 2 sin α = 1 – d/ (4 h

^{2}+ d

^{2})

^{½}.

9. What is the shape factor for a hemispherical bowl with respect to itself of diameter d? The cavity is closed on its outer surface with a flat plate

a) 1.5

b) 1

c) 0.5

d) 2.5

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_{11}= 1 – A

_{2 }/ A

_{1 }= 0.5.

10. Consider a system of concentric spheres of radius r_{ 1} and r_{ 2} (r_{ 2} is greater than r_{ 1}). If r_{ 1} = 5 cm, determine the radius r_{ 2} if it is desired to have the value of shape factor F _{21} equal to 0.6

a) 6.45 cm

b) 7.45 cm

c) 8.45 cm

d) 9.45 cm

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_{1 }F

_{12 }= A

_{ 2}F

_{21}.

## Set 2

1. Ratio of inertia force to viscous force is known as

a) Grashof number

b) Reynolds number

c) Peclet number

d) Stanton number

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2. The ratio of heat flow rate by convection to flow rate by conduction is known as

a) Stanton number

b) Graetz number

c) Fourier number

d) Peclet number

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3. The ratio of heat capacity of fluid flowing through the pipe per unit of length to the conductivity of pipe material is known as

a) Graetz number

b) Reynolds number

c) Peclet number

d) Fourier number

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4. Identify the correct statement

a) Peclet number = (Graetz number) (Fourier number)

b) Peclet number = (Stanton number) (Fourier number)

c) Peclet number = (Reynolds number) (Prandtl number)

d) Peclet number = (Graetz number) (Reynolds number)

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5. What is the value of Prandtl number for highly viscous oils?

a) 100-1000

b) 0-100

c) 10-100

d) 100-10000

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6. What is the value of Prandtl number for liquid metals?

a) 0.003-0.01

b) 0.01-0.1

c) 0.1-0.5

d) 0.5-0.95

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7. The product of buoyant force and inertia force to the square of the viscous force is known as

a) Stanton number

b) Grashof number

c) Fourier number

d) Peclet number

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8. The ratio of heat transfer coefficient to the flow of heat per unit temperature rise due to the velocity of the fluid is known as

a) Fourier number

b) Grashof number

c) Peclet number

d) Stanton number

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9. Which number indicates the relative ability of the fluid to diffuse momentum and internal energy by molecular mechanisms?

a) Nusselt number

b) Prandtl number

c) Peclet number

d) Stanton number

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10. Which number establishes the relation between convective film coefficient, thermal conductivity of the fluid and a significant length parameter?

a) Nusselt number

b) Stanton number

c) Peclet number

d) Fourier number

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## Set 3

1. Which one is having highest value of solar absorptivity?

a) White marble

b) Concrete

c) Asphalt

d) Snow

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2. What is the value of solar absorptivity for aluminum foil?

a) 0.15

b) 0.16

c) 0.17

d) 0.18

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3. What is the value of solar absorptivity for polished copper?

a) 0.17

b) 0.18

c) 0.19

d) 0.20

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4. Which one is having lowest value of solar absorptivity?

a) Snow

b) Red brick

c) Aluminum foil

d) Polished aluminum

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5. What is the value of solar absorptivity for polished stainless steel?

a) 0.37

b) 0.36

c) 0.35

d) 0.34

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6. Which one is having lowest value of solar absorptivity?

a) Black paint

b) Dull stainless steel

c) Concrete

d) White marble

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7. What is the value of solar absorptivity for white marble?

a) 0.45

b) 0.46

c) 0.47

d) 0.48

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8. Which one is having highest value of solar absorptivity?

a) Red brick

b) Asphalt

c) Black paint

d) White paint

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9. What is the value of solar absorptivity for asphalt?

a) 0.90

b) 0.80

c) 0.70

d) 0.60

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10. What is the value of solar absorptivity for snow?

a) 0.25

b) 0.26

c) 0.27

d) 0.28

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## Set 4

1. The heat energy absorbed by a known area in a fixed time is determined with the help of an instrument called

a) Psychrometer

b) Pyrheliometer

c) Thermometric well

d) Any instrument

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2. The observed solar constant S_{0}, the true solar constant S and the angular elevation Z of the sun are related by the expression

a) S_{0} =S a ^{SEC Z}

b) S_{0} =2 S a ^{SEC Z}

c) S_{0} =3 S a ^{SEC Z}

d) S_{0} =4 S a ^{SEC Z}

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_{0}along y-axis and sec Z along x-axis, the intercept log S on the y-axis is found.

3. The value of solar constant varies between

a) 1123 and 1237 W/m^{2}

b) 1345 and 1453 W/m^{2}

c) 1987 and 2346 W/m^{2}

d) 1335 and 1815 W/m^{2}

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^{2}.

4. The total amount of heat energy received by the sphere of radius r is

a) 2 π R^{2} S

b) 6 π R^{2} S

c) 4 π R^{2} S

d) π R^{2} S

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^{2}.

5. Amount of heat energy radiated by unit surface of the sun in the same time workout as

Take, R = mean distance of earth from the sun and r = radius of sun

a) E = π R^{2} S/4 π R^{2}

b) E = 4 π R^{2} S/4 π R^{2}

c) E = 4 π R^{2}

d) E = 4 π R^{2} S

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^{2}S to 4 π R

^{2}.

6. Temperature of sun can be workout from

a) Wein’s displacement law

b) Stefan-Boltzmann law

c) Kirchhoff’s law

d) All of the Mentioned

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_{MAX}T = 2-89 * 10

^{ -3}m K.

7. The temperature of the photosphere, referred to as the effective temperature of the sun, is usually taken as

a) 3000 K

b) 4000 K

c) 5000 K

d) 6000 K

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8. The approximate distribution of the flow of sun’s energy to the earth’s surface is

a) 53% is reflected back to space

b) 53% is transmitted to the earth

c) 9% is scattered

d) 22% is absorbed in the atmosphere

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9. The solar radiation that is felt at the earth’s surface includes

(i) Direct radiation that has passed through the atmosphere

(ii) Diffuse radiation from the sky

(iii) Absorbed radiation from the water

Identify the correct statement

a) 1 only

b) 1 and 2

c) 1, 2 and 3

d) 2 and 3

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10. When the sun lies at a mean distance from the earth, the heat flux from the sun to the outer edge of the atmosphere has been found to be

a) 2350 W/m^{2}

b) 3350 W/m^{2}

c) 4350 W/m^{2}

d) 1350 W/m^{2}

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## Set 5

1. What is the value of specific heat for brick in J/kg K?

a) 835

b) 735

c) 635

d) 535

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2. Which one is having highest value of specific heat?

a) Asphalt

b) Bakelite

c) Chrome brick

d) Fire clay

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3. What is the value of specific heat for asphalt in J/kg K?

a) 920

b) 820

c) 720

d) 620

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4. What is the value of specific heat for Bakelite in J/kg K?

a) 1665

b) 1565

c) 1465

d) 1365

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5. Which one is having lowest value of specific heat?

a) Coal

b) Clay

c) Banana

d) Concrete

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6. What is the value of specific heat for coal in J/kg K?

a) 1260

b) 1360

c) 1460

d) 1560

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7. What is the value of specific heat for cotton in J/kg K?

a) 1600

b) 1500

c) 1400

d) 1300

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8. Which one is having highest value of specific heat?

a) Sand

b) Berea

c) Magnesite

d) Limestone

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9. What is the value of specific heat for sand in J/kg K?

a) 800

b) 700

c) 600

d) 500

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10. Which one is having lowest value of specific heat?

a) Ice

b) Pyrex

c) Paraffin

d) Rubber