Multiple choice

A solid sphere of radius r1 = 20 mm is placed concentrically inside a hollow sphere of radius r2 = 30 mm as shown in the figure.

The view factor F21 for radiation heat transfer is

  1. $\frac{2}{3}$
  2. $\frac{4}{9}$
  3. $\frac{8}{27}$
  4. $\frac{9}{4}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Correct option is (2).

A solid sphere of radius $r_1 = 20 mm$ placed inside concentrically inside a hollow sphere of radius $r_2 = 300mm$ as shown in figure.

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