Question

Radiation between a flat black surface and a hollow black hemisphere is of interest for a selected application. The view factor (F21) of the hemisphere to the flat surface (1) is

A. 0.36
B. 0.5
C. 0.64
D. 0.67
E.1

Answer 1

The correct view factor (F21) from a hollow black hemisphere to a flat black surface is 0.5, following the general geometric relationship of a hemisphere to its base.

Step-by-step explanation:

The question asked involves determining the view factor (F21) from a hollow black hemisphere to a flat black surface. The view factor, also known as configuration factor or form factor, is a dimensionless quantity used in radiation heat transfer to relate the geometric configuration of two surfaces. From the given options, the correct answer is B. 0.5. This follows from the fact that a hemisphere has a view factor of 0.5 towards its base. In this case, the base of the hemisphere is the flat black surface in question (Surface 1).