How will you differentiate between a star and an artificial satellite in night sky ?

Correct option is A

The correct answer is (a).
Explanation
Stars appear to twinkle in the night sky due to atmospheric refraction of their light as it passes through different layers of air. Artificial satellites, on the other hand, do not twinkle and appear as steady points of light moving smoothly across the sky. This difference in twinkling helps us distinguish between a star and an artificial satellite.
Additional Information
• Option {b} is incorrect because speed is difficult to judge accurately with the naked eye. • Option {c} is incorrect because both stars and satellites appear as point sources of light. • Option {d} is incorrect because colour is not a reliable distinguishing feature.