Previous Year Question
Consider the following statements.
The albedo of an object determines its visual brightness when viewed with reflected light.
The albedo of Mercury is much greater than the albedo of the Earth.
Which of the statements given above is/are correct?
Correct Answer: A
Detailed Solution
Statement 1 is correct.
Albedo represents the fraction of incident light reflected by a body or surface.
A high-albedo object reflects more light and appears brighter under comparable illumination and viewing conditions.
A low-albedo object absorbs more light and consequently appears darker.
Actual observed brightness is also affected by the object’s size, distance and phase angle, but albedo measures its intrinsic reflectivity.
Statement 2 is incorrect.
Mercury’s geometric albedo is approximately 0.106.
Earth’s geometric albedo is approximately 0.367.
Mercury’s albedo is therefore substantially lower—not much greater—than that of Earth.