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The travel time of light from the Sun to Earth is a frequently tested astronomical fact. Option A (499 seconds = 8 min 19 sec) is CORRECT. The image states: सूर्य से पृथ्वी तक प्रकाश के पहुँचने में लगभग कितना समय लगता है — 499 सेकंड या 8 मिनट 19 सेकंड. The average distance from Sun to Earth is approximately 1 AU = 1.496 × 10¹¹ m. Speed of light = 3 × 10⁸ m/s. Time = Distance/Speed = 1.496×10¹¹ / 3×10⁸ ≈ 499 seconds ≈ 8 minutes 19 seconds. This means we see the Sun as it was 8 minutes 19 seconds ago not as it is right now. Option B (1 min 28 sec) is wrong. This is the time for reflected light from the MOON to reach Earth not the Sun. Moon is much closer to Earth (avg 384,400 km). Option C (24 hours) is wrong. In 24 hours light would travel 24×3600×3×10⁸ = 2.6×10¹³ m which is much farther than the Sun-Earth distance. Option D (1 year) is wrong. One light-year is the distance light travels in one year (9.46×10¹⁵ m). The Sun is only about 8.3 light-minutes away not 1 light-year.
FAQ
Common questions and clear answers for this topic.
Optics is the branch of physics that studies the behavior of light, including its reflection, refraction, and interaction with lenses and mirrors.
Reflection is the bouncing back of light when it strikes a surface, while refraction is the bending of light as it passes from one medium to another with a different optical density.
A lens is a transparent optical device with curved surfaces that refracts light to converge or diverge rays, commonly classified as convex (converging) or concave (diverging).
The speed of light in a vacuum is approximately 3 x 10^8 meters per second, denoted by the symbol c.
Total internal reflection occurs when light traveling from a denser medium to a rarer medium strikes the boundary at an angle greater than the critical angle, causing it to be completely reflected back into the denser medium.
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