InterviewSolution
Saved Bookmarks
| 1. |
The solar constant for the earth is Σ. The surface temperature of the sun is T K. The sun subtends an angle θ at the earth.(a) Σ ∝ T4(b) Σ ∝ T2(c) Σ ∝ θ2(d) Σ ∝ θ |
|
Answer» Correct Answer is; (a) Σ ∝ T4 , (c) Σ ∝ θ2 Let R = radius of the sun, d = distance of the earth from the sun. Power radiated by the sun = (4πR2) σT4 =P. Energy received per unit area per second normally on the earth = Σ = P/4πd2 = 4πR2σT4 / 4πd2 = (σT4) (R/d)2 = 1/4 σT4 (2R/d)2 Angle subtended by the sun at the earth = θ 2R/d. or Σ = constant x T4 x θ2. |
|