Project ForgeHeat Transfer
Convection & Radiation
GATE 2019
Easy
Sphere 1 with a diameter of 0.1 m is completely enclosed by another sphere 2 of diameter 0.4 m. The view factor F12 is
- A0.0625
- B0.25
- C0.5
- 1.0
Explanation
Since sphere 1 is completely (and convexly) enclosed by sphere 2, every ray of radiation leaving sphere 1's surface must strike sphere 2 — none of it can return to hit sphere 1 itself (it's convex). So F12=1.0.
Source: GATE ME 2019 Session 2 (Set 3) (2019)
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