The average intensity of sunlight impinging on Earth is measured to be about 1.4 kW/m².What is the power of sunlight emitted by the sun? (Earth-Sun distance = 1.5 × 10⁸ km,Earth radius = 6.4 × 10³ km) A)4.0 × 10²⁶ W B)3.2 × 10²² W C)7.2 × 10¹⁴ W D)7.6 × 10⁸ W

Question

Quizplus · Accepted Answer

The power of sunlight emitted by the sun can be calculated using the formula for the power intercepted by Earth: $P = I \times A$, where $I$ is the intensity of sunlight (1.4 kW/m^2 = 1.4 × 10^3 W/m^2) and $A$ is the surface area of a sphere with a radius equal to the Earth-Sun distance (1.5 × 10^11 m). The area $A$ of a sphere is given by $4\pi r^2$. Substituting the given values, $A = 4\pi (1.5 × 10^{11})^2$, and then multiplying by the intensity, we find the total power output of the sun. This calculation yields a value in the order of 10^26 watts, making choice A (4.0 × 10^26 W) the correct answer.

The Average Intensity of Sunlight Impinging on Earth Is Measured