A point source of light is placed at the bottom of a vessel which is filled with water of refractive index `mu` to a height h. If a floating opaque disc has to be placed exactly above it so that the source is invisible from above, the radius of the disc should be-

A point source of light is placed at a depth of h below the surface of water of refractive index mu . A floating opaque disc is placed on the surface of water so that light from the source is not visible from the surface. The minimum diameter of the disc is

A point source of light is placed at a depth of h below the surface of water of refractive index mu . A floating opaque disc is placed on the surface of water so that light from the source is not visible from the surface. The minimum diameter of the disc is

A point source of light S is placed at the bottom of a vessel containg a liquid of refractive index 5//3. A person is viewing the source from above the surface. There is an opaque disc of radius 1 cm floating on the surface. The centre of the disc lies vertically above the source S. The liquid from the vessel is gradually drained out through a tap. What is the maximum height of the liquid for which the source cannot at all be seen from above?

An isotropic point source is placed at a depth h below the water surface. A floating opaque disc is placed on the surface of water so that the source is not visible from the surface. What is the minimum radius of the disc? Take refractive index of "water"=mu .

An isotropic point source is placed at a depth h below the water surface. A floating opaque disc is placed on the surface of water so that the source is not visible from the surface. What is the minimum radius of the disc? Take refractive index of "water"=mu .

An isotropic point source is placed at a depth h below the water surface. A floating opaque disc is placed on the surface of water so that the source is not visible from the surface. What is the minimum radius of the disc? Take refractive index of "water"=mu .

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 of radius 1 cm floating on the surface. The centre of disc lies vertically above the source O . The liquid from the vessel is gradually drained out through a tap. What is the maximum height of the liquid for which the source cannot be seen at all.