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General
Easy
Question
A point source of light S is placed at the bottom of a vessel containing a liquid of refractive index 5/3. A person is viewing the source from above the surface. There is an opaque disc D of radius 1 cm floating on the surface of the liquid. The centre of the disc lies vertically above the source S. The liquid from the vessel is gradually drained out through a tap. The maximum height of the liquid for which the source cannot be seen at all from above is
- 1.50 cm
- 1.64 cm
- 1.33 cm
- 1.86 cm
The correct answer is: 1.33 cm
Suppose the maximum height of the liquid is h for which the source is not visible.
Hence radius of the disc
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