Question

Definition of solar constant

Answer 1

the rate at which energy reaches the earth's surface from the sun, usually taken to be 1,388 watts per square metre.

Answer 2

Solar constant is 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’smean distance from the Sun. It is most accurately measured from satellites where atmospheric effects are absent. The value of the constant is approximately 1.366 kilowatts per square metre.