# Test: Stefan Boltzmann Law

## 10 Questions MCQ Test Heat Transfer for Engg. | Test: Stefan Boltzmann Law

Description
This mock test of Test: Stefan Boltzmann Law for Chemical Engineering helps you for every Chemical Engineering entrance exam. This contains 10 Multiple Choice Questions for Chemical Engineering Test: Stefan Boltzmann Law (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Stefan Boltzmann Law quiz give you a good mix of easy questions and tough questions. Chemical Engineering students definitely take this Test: Stefan Boltzmann Law exercise for a better result in the exam. You can find other Test: Stefan Boltzmann Law extra questions, long questions & short questions for Chemical Engineering on EduRev as well by searching above.
QUESTION: 1

### The Stefan-Boltzmann constant has units of

Solution:

According to Stefan-Boltzmann law, q = α A T4.

QUESTION: 2

### According to Stefan-Boltzmann law of thermal radiation

Solution:

α is Stefan-Boltzmann constant whose value is 5.67 * 10 -8 W/m2 K4.

QUESTION: 3

### Calculate the radiant flux density from a black surface at 400 degree Celsius?

Solution:

E = σ T4 = 5.67 * 10 –8 (400 + 273)4 = 11631.7 W/m2.

QUESTION: 4

If the emitted radiant energy is to be doubled, to what temperature surface of black body needs to be raised? Take radiant flux density as 11631.7 W/m2.

Solution:

2(11631.7) = 5.67 * 10 –8 T 4.

QUESTION: 5

A furnace having inside temperature of 2250 has a glass circular viewing of 6 cm diameter. If the transmissivity of glass is 0.08, make calculations for the heat loss from the glass window due to radiation

Solution:

Q = σ A T4 (t) = 328.53 W.

QUESTION: 6

The value of radiation coefficient or the Stefan-Boltzmann constant is

Solution:

q = α A T4.

QUESTION: 7

Measurements were made of the monochromatic absorptivity and monochromatic hemispherical irradiation incident on an opaque surface, and the variation of these parameters with wavelength may be approximated by the result shown below. Determine the total hemispherical absorptivity Solution:

Incident flux = 800(8 – 2) – 4800 W/m2. Absorptivity = 3200/4800 = 0.667.

QUESTION: 8

What is the wavelength band for Ultraviolet rays?

Solution:

This is the maximum and minimum wavelength for Ultraviolet rays.

QUESTION: 9

A black body of total area 0.045 m2 is completely enclosed in a space bounded by 5 cm thick walls. The walls have a surface area 0.5 m 2 and thermal conductivity 1.07 W/ m K. If the inner surface of the enveloping wall is to be maintained at 215 degree Celsius and the outer wall surface at 30 degree Celsius, calculate the temperature of the black body

Solution:

Q= σ A (T b– Tw4), Q c = k A d t/δ = 1979.5 W. So temperature of black body is 955.9 K.

QUESTION: 10

What is the wavelength band for solar radiation?

Solution:

This is the maximum and minimum wavelength for solar radiation.