Ray Optics and ...

In refraction of light through a glass slab, the directions of the incident ray and refracted ray are:

The focal point of an equi- convex lens whose refractive index is $$1.5$$ is $$10\ cm$$ in air. Its focal point inside a liquid of refractive index $$1.25$$ is 

An object placed at a distance of 16 cm from first principal focus of convex lens, produces a real image at a distance of 36 cm from its second principal focus. Then the focal length of the lens is :

In a thin spherical fish bowl of radius $$10\ cm$$ filled with water of refractive index $$\dfrac{4}{3}$$, there is a fish at a distance of $$4\ cm$$ there is a small fish at a distance of $$4\ cm$$ form the center $$C$$ as shown. The image of the fish appears, when seen from the point $$D$$ would be

A plane mirror is made of glass slab $$(n=1.5)2.5 cm$$ thick and silvered back. A point object placed $$5 cm$$ in front the unsilvered face of the mirror. The position of final image is:

A student while observing a coin placed at the bottom of the container filled with water finds it to be at 2 m depth .To observe the  coin at its actual depth he should use

How much water should be filled in a container $$21 cm$$ in height, so that it appears half filled when viewed from the top of the container? (given that $$a \mu_\omega$$ = 4/3)  

A ray of light passes normally through a slab $$(\mu = 1.5)$$ of thickness $$'t'$$. If the speed of light in vacuum be $$'c'$$ then time taken by the ray to go across the slap will be

Choose the wrong statement related to refraction of light

Four identical lenses are kept one beside the other on the same optical as shown in the figure. The right surface of rightmost lens is silvered. Focal length of lens is 20 cm and radius of silvered is 20 cm. The focal length of the combined system is