Test: Reflectivity

# Test: Reflectivity

Test Description

## 10 Questions MCQ Test Heat Transfer | Test: Reflectivity

Test: Reflectivity for Chemical Engineering 2022 is part of Heat Transfer preparation. The Test: Reflectivity questions and answers have been prepared according to the Chemical Engineering exam syllabus.The Test: Reflectivity MCQs are made for Chemical Engineering 2022 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests for Test: Reflectivity below.
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Test: Reflectivity - Question 1

### Reflectivity is defined as

Detailed Solution for Test: Reflectivity - Question 1

It is total energy reflected by the body. Its value depends upon the nature of the surface of the body, its temperature and wavelength of incident radiations.

Test: Reflectivity - Question 2

### Of the radiant energy 350W/m2 incident upon a surface 250W/m2 is absorbed, 60W/m2 is reflected and the remainder is transmitted through the surface. Workout the value for reflectivity for the surface material

Detailed Solution for Test: Reflectivity - Question 2

Reflectivity = fraction of total energy reflected by the body = 60/350 = 0.171.

Test: Reflectivity - Question 3

### A thin metal plate of 4 cm diameter is suspended in atmospheric air whose temperature is 290 K. This plate attains a temperature of 295 K when one of its face receives radiant energy from a heat source at the rate of 2 W. If heat transfer coefficient on both surfaces of the plate is stated to be 87.5 W/m 2 K, workout the energy lost by reflection

Detailed Solution for Test: Reflectivity - Question 3

Heat loss by convection from both sides of the plates = 2 h A d t = 1.1 W. Energy lost by reflection = 2.0 – 1.1 = 0.9 W.

Test: Reflectivity - Question 4

The value of reflectivity depends upon
(i) Body temperature
(iii) Nature of surface of body
Identify the correct statement

Detailed Solution for Test: Reflectivity - Question 4

It should be wavelength of incident radiation. It is the fraction of total energy reflected by the body.

Test: Reflectivity - Question 5

When a surface absorbs a certain fixed percentage of striking radiation the surface is called

Detailed Solution for Test: Reflectivity - Question 5

It is absorbing a certain fixed amount of radiations.

Test: Reflectivity - Question 6

Which one is true regarding gases?

Detailed Solution for Test: Reflectivity - Question 6

Gases are known to reflect very little of the radiation incident on their surface.

Test: Reflectivity - Question 7

Thin glass plate is an example of

Detailed Solution for Test: Reflectivity - Question 7

For transparent body, transmissivity is zero.

Test: Reflectivity - Question 8

Radiant energy with an intensity of 800 W/m2 strikes a flat plate normally. The absorptivity is thrice the reflectivity and twice the transmissivity. Determine the rate of reflection

Detailed Solution for Test: Reflectivity - Question 8

Rate of reflection = pQ= 218.20 W/m2.

Test: Reflectivity - Question 9

The total radiant energy A impinging upon a body would be partially or totally absorbed, reflected from its surface or transmitted through it. Identify the correct statement

Detailed Solution for Test: Reflectivity - Question 9

A = B + C + D.

Test: Reflectivity - Question 10

Which one is true for opaque body?

Detailed Solution for Test: Reflectivity - Question 10

For opaque body, sum of absorptivity and reflectivity is unity.

## Heat Transfer

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