Question

a glass slab is placed in the path of convergent light the point of convergence of light

Answer 1

think of what happens to the light as it travels into the glass

the light refracts ..

so if its converging it has a bit of an angle to the NORMAL of the glass surface

n1 sin A1 = n2 sin A2

is snells law

n1 = air = 1

n2 = glass= 1.5

sin A1 = n2 sin A2

solve for A2

sin A2 = (sin A1)/n2

this means A2's angle will be smaller than A1

this means the light will bend a bit toward the normal

.......A2

......|...r

......|..r

......|.r

......*==== glass surface

....*.|

..*...|

*.....|

A1

see how the stars which are the light coming into the surface bend slightly this bending means that the light will take longer to converge

Answer 2

last wala hai ispe bhi karde