2017 · Q3
Statement IOccasionally we see two rainbows together, the primary rainbow with another less intense secondary rainbow about 10 degrees away.
Statement IIThe secondary rainbow appears due to refraction after a reflection of sunlight from the water droplets.
general-sciencephysics-light-electricity
- ABoth the statements are individually true and Statement II is the correct explanation of Statement I
- BBoth the statements are individually true but Statement II is NOT the correct explanation of Statement I
- CStatement I is true but Statement II is false
- DStatement I is false but Statement II is true
Explanation
Statement I is true: a fainter secondary rainbow is often seen roughly 8–10 degrees outside the primary bow (the primary is centred about 42° from the antisolar point, the secondary about 51°). Statement II describes the secondary bow as forming by refraction after a reflection of sunlight in raindrops; strictly, the secondary rainbow needs two internal reflections (which is why it is fainter and its colours are reversed), so the statement is a simplified but acceptable description – key disputed, since at least one verified key marks Statement II false for omitting the second internal reflection. Treating both statements as true, with II not being the precise explanation of the double bow in I, the keyed answer is (B).