Physics

Problem

It takes light about 500 s to reach the Earth from the Sun. a. a** Determine the average radius of the Earth's orbit around the Sun. (The speed of light is

3 \times 10^8 \text{ ms}^{-1}

). b. b** If the Sun's luminosity is

L_{\odot} = 3.83 \times 10^{26} \text{ W}

, show that the solar constant,

S

, for the Earth is about

1.4 \text{ kWm}^{-2}

. c. c** The average solar power per unit area received by the Earth is only

\frac{1}{4}

of this value. Suggest a reason for this. d. d** The average solar power per unit area incident on the Earth's surface is about

245 \text{ Wm}^{-2}

. Suggest why this value is less than

\frac{1}{4}

1.4 \text{ kWm}^{-2}

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