Rainbow — PrimaryMediumQuestion 20242
Question
In a primary rainbow, the angle of the bow (from anti-solar point) is about 42°. It forms because:
- ALight reflects once inside the raindrop and refracts twice — minimum deviation at about 42°Correct
- BLight undergoes TIR in a raindrop
- CLight reflects twice inside the drop
- DWater absorbs certain wavelengths
Correct answer
Light reflects once inside the raindrop and refracts twice — minimum deviation at about 42°
Explanation
Sunlight enters a raindrop, refracts, reflects once at the back surface, and refracts out. Different colours have different minimum deviation angles (red ≈ 42°, violet ≈ 40°). The rainbow appears at these minimum deviation angles.