The estimated value of the solar constant is 1.366 kilowatts per second per square metre. The solar constant is used to quantify the rate at which energy is received upon a unit surface such as a solar panel.
Explanation
Solar constant, the total radiation energy received from the Sun per unit of time per unit of area on a theoretical surface perpendicular to the Sun’s rays and at Earth’s mean distance from the Sun. It is a measurement of the solar electromagnetic radiation available in a meter squared at Earth’s distance from the sun.