A point source of light is kept below the surface of water (n_(w) = 4//3) at a depth of sqrt(7)m. The radius of the circular bright patch of light noticed on the surface of water is :

A point source of light is kept below the surface of water (n_(w) = 4/

1.	A point source of light is kept below the surface of water (n_(w) = 4//3) at a depth of sqrt(7)m. The radius of the circular bright patch of light noticed on the surface of water is :
Answer» `sqrt(7) m` `(3)/(sqrt(7))m` 3m `(sqrt(7))/(3)m`. Solution :(c ) When the ray of light is incident from water air interface at critical angle `(theta_(c))`, the refracted becomes PARALLEL to the interface. Hence, the radius of the CIRCULAR bright patch oflight noticed on the surface of water is GIVEN by `R h tan theta_(c )` `=sqrt(7)(sintheta_(c))/(costheta_(c))=sqrt(7)(1//mu)/(sqrt(1-(1)/(mu^(2))))=(sqrt(7))/(sqrt(mu^(2)-1))=3m`

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A point source of light is kept below the surface of water (n_(w) = 4//3) at a depth of sqrt(7)m. The radius of the circular bright patch of light noticed on the surface of water is :

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