Consider the following statements: Which of the statements given above is/are correct?

Answer: (a) 1 only

Albedo means reflectivity; Mercury reflects less than Earth.

Statement by statement

1. ✓ CORRECT Albedo decides how bright an object looks in reflected light.

2. ✗ WRONG Mercury’s albedo (~0.1) is LOWER than Earth’s (~0.3).

The idea

A surface looks bright in reflected light partly because of its albedo, the fraction of incident light it returns. Being close to the Sun increases illumination but does not automatically make the surface more reflective. Dark rock can absorb a large fraction of even intense sunlight. Clouds can make a planet more reflective than a bare rocky surface.

Why the others are wrong

(b) Accepts a brighter Mercury.

(c) Accepts a brighter Mercury.

(d) Rejects the definition.

The trap

Mercury is close to the Sun, so it “should” be bright — but its dark rock reflects little.

Elimination technique

Separate incident light from reflected fraction. Mercury’s proximity to the Sun cannot justify a larger albedo; its dark rocky surface removes statement 2 from this comparison. Statement 1 identifies the role of reflectivity.

Also know

Venus has a bright thick cloud cover; Earth’s reflection combines clouds, oceans, ice and land. The Moon and Mercury have relatively dark exposed surfaces. Bond albedo measures the fraction of all incident solar energy reflected; geometric albedo describes brightness in a particular viewing comparison. Use the same albedo definition when comparing numerical values.