Test: Gaseous Radiations - Mechanical Engineering MCQ

Some of the gases have low emissive power and absorptivity. They are considered practically diathermanous. Which of the following option is true?

Consider an enclosure formed by three surfaces having the following values of shape factors, emissivities and temperatures 

Surface 1 i.e. curved cylindrical has an emissivity 0.75 and temperature 800 K
Surface 2 i.e. closing disc has an emissivity 0.8 and temperature 700 K
Surface 3 i.e. closing disc has an emissivity 0.8 and temperature 700 K
The closing flat discs are 25 mm in diameter and they have interspacing distance equal to 100 mm. If the shape factor between these two identical discs is 0.05, calculate the net rate of radiant heat flow from the curve surface to each of the closing end surface

Consider a beam of monochromatic radiation at wavelength λ that enters a layer of absorbing gas. As the beam passes through the gas layer, its intensity

When a gas or vapor is in the process of oxidation and combustion, it is called as

The monochromatic absorption coefficient depends upon
(i) Temperature
(ii) Time
(iii) Pressure
(iv) Wavelength
Identify the correct option

Which one of the following is not extremely inert to thermal radiation?

Consider a beam of monochromatic radiation at wavelength λ that enters a layer of absorbing gas. As the beam passes through the gas layer, its intensity is given by