The correct answer is Option 1: 1 only.

Statement 1: The albedo of an object determines its visual brightness when viewed with reflected light.

This statement is correct. Albedo refers to the amount of light that an object reflects back into space compared to the amount of light it receives. It is measured as a ratio from 0 to 1, where 0 represents a perfectly absorbing (black) surface, and 1 represents a perfectly reflecting (white) surface. The higher the albedo, the brighter the object appears when viewed with reflected light. This is because a higher albedo means more light is reflected back, making the object appear brighter.

Statement 2: The albedo of Mercury is much greater than the albedo of the Earth.

This statement is incorrect. In reality, the albedo of Mercury is much lower than the albedo of Earth. Mercury is a rocky planet with a relatively dark surface, similar to the Moon. Its average albedo is around 0.12, which means it reflects only about 12% of the sunlight that hits it. In contrast, Earth has an average albedo of about 0.31, reflecting approximately 31% of the sunlight it receives. Earth`s higher albedo is primarily due to its cloud cover, oceans, and ice caps, which reflect a significant amount of sunlight back into space.

It is important to note that albedo can vary across different parts of a planet or object. For example, Earth`s albedo varies depending on the surface type (land, ocean, ice) and cloud cover. Similarly, Mercury`s albedo can vary based on the composition and texture of its surface, which includes areas with higher reflectivity, such as certain crater floors, and areas with lower reflectivity, such as dark volcanic plains.

In conclusion, only Statement 1 is correct. The albedo of an object does determine its visual brightness when viewed with reflected light, but Statement 2 is incorrect as the albedo of Mercury is lower than the albedo of Earth.