Consider the following statements:1. Size of the sun at dusk2. Colour of the sun at dawn3. Moon being visible at dawn4. Twinkle of stars in the sky5. Polestar being visible in the skyWhich of the above are optical illusions?
✓ Correct answer: c) 1, 2 and 4
ExplanationAn optical illusion is characterized by visually perceived images that differ from object than reality.The information that is gathered by the eye is processed in the brain that gives a perception that does not tally with a physical measurement of the stimulus source.Statement 1 is correct: There are no known objects of a similar size as the sun (or moon) when it is high in the sky.The sun, however, appears even larger when it is low in the sky because we can see distant objects near the horizon that we know to be large.Thus, the size of the sun at dusk is a visual illusion.Statement 2 is correct: There are many different colours in light.Red is the colour that moves the farthest out of all of those others.As the sun sets, crimson (deep, rich red colour) is the final hue to be seen.Red is the last colour to appear when the other colours begin to fade.Therefore, the colour of the sun at dawn is due to optical illusion.Statement 3 is incorrect: Moon being visible at dawn is not an optical illusion as the moon is visible somewhere in the sky at dawn during the entire half of t
Practice more Science PYQs
Attempt a free 10-question quiz or browse the full Science & Technology previous-year-question bank with instant answers and explanations.
🔬 Science PYQs →