Reflection is a phenomenon which occurs in opaque objects but reflection occurs in a droplet of water at the time of rainbow formation. Explain how?
1 Answer
Reflection of light from a mirror and reflection occurring in a droplet of water at the time of rainbow formation are two different physical phenomena.
Explanation:
The statement asserted in the question
"Reflection is a phenomenon which occurs in opaque objects" is incorrect. Light can not travel in opaque objects.
The scientific dictionary defines Opaque:
Adjective. Neither reflecting nor emitting light. Allowing little light to pass through, not translucent or transparent.
What perhaps in the mind of the student is:
Reflection takes place whenever ray of light travels from a transparent medium towards an opaque medium (shown in the figure below). The opaque medium does not let the light pass through. Instead reflects it back as per laws of reflection.
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Why does reflection occur in a droplet of water at the time of rainbow formation. Both the droplet of water as well as the medium in which droplet is there (air), are transparent; absence of an opaque medium.
We must remember that reflection in the water droplet at the time of rainbow formation is total internal reflection. This occurs a when a ray of light, while traveling from a denser to rarer medium, reaches an interface and makes an angle of incidence exceeding the critical angle, as explained in the figure below.
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Total internal refection in a water droplet and formation of rainbow.
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