Question

Refractive index of water is 5/3. A light source is placed in water at a depth of 4 m. Then what must be the minimum radius of disc placed on water surface so that the light of source can be stopped?

(a) 3 m

(c) 5 m

(b) 4 m

(d) ∞

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Answer 1

Explanation:

(b) 4 m

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