Nicolle Katherine
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Quiz on Heat Transfer quiz 2 Ramirez, created by Nicolle Katherine on 28/07/2015.

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Nicolle Katherine
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Heat Transfer quiz 2 Ramirez

Question 1 of 10

1

A concrete wall consist of 450 mm red clay brick with thermal conductivity of 1 (SI units). It is lined on the inner face with 15 mm gypsum plaster with thermal conductivity of 0.4 (SI units). If the inside wall surface is maintained at 25 deg C and the outside wall surface temperature of the brick is 37 deg. C. Determine the heat flow per unit area.

Select one of the following:

  • 13.2

  • 24.6

  • 25.9

  • 14.1

Explanation

Question 2 of 10

1

Estimate the temperature in the previous number between the brick and the gypsum in deg C.

Select one of the following:

  • 13.2

  • 24.6

  • 25.9

  • 14.1

Explanation

Question 3 of 10

1

Water is cooled in a double pipe counter current heat exchanger from 120 deg C to 100 deg C with air entering at 60 deg C and leaving at 75 deg. C. The LMTD for the heat exchanger is 

Select one of the following:

  • 4.245 deg C

  • 42.45 deg C

  • 53.2 deg C

  • 5.32 deg C

Explanation

Question 4 of 10

1

You are asked to design cylindrical steel rod if 50.0 cm long with a circular cross section, that will conduct 150 W from a furnace at 400 deg C to a container of boiling water under 1 atm. What must the rod's diameter be?

Select one of the following:

  • 6 cm

  • 7 cm

  • 8 cm

  • 9 cm

Explanation

Question 5 of 10

1

What is the Absorptivity of concrete at 3333.6 K?

Select one of the following:

  • 0.35

  • 0.45

  • 0.55

  • 0.65

Explanation

Question 6 of 10

1

A pot with a steel bottom 8.5 mm thick rests on a hot stove. The are of the bottom of the pot is 150 m2 . The water inside the pot is at 100 deg C and 0.39 kg are evaporated every 3 minutes. Find the temperature of the lower surface of the pot, which is in contact with the stove.

Select one of the following:

  • 105.5 deg C

  • 273.5 deg K

  • 105.5 deg K

  • 273,5 deg C

Explanation

Question 7 of 10

1

The hot glowing surfaces of the starts emit energy in the form of electromagnetic radiation. It is a good approximation to assume emissivity = 1 for these surfaces. Find the Radii of rigel, the brigh blue start in the constellation orion which radiates energy at a rate of 2.7 x 1023 W and has a surface temperature of 11000 K.

Select one of the following:

  • 3 16 100 000 000 m

  • 2 16 100 000 000 m

  • 1 16 100 000 000 m

  • 16 100 000 000 m

Explanation

Question 8 of 10

1

Among liquids, water has a comparatively high value of thermal conductivity, due to its

Select one of the following:

  • low density

  • high viscosity

  • partial ionization

  • dense structure

Explanation

Question 9 of 10

1

The sum of reflectivity and absorptivity for an opaque body is equal to

Select one of the following:

  • 0.5

  • 1

  • 2

  • 0

Explanation

Question 10 of 10

1

The ratio of kinematic viscosity to thermal diffusivity is called the __________ number.

Select one of the following:

  • Peclet

  • Stanton

  • Pradtl

  • Nusselt

Explanation

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