Question

4. Light travels from air into glass slab of thickness 50 cm and refractive index 1.5.

(a) What is the speed of light in glass?

(b) What is the time taken by the light to travel through the glass slab?

(c) What is the optical path of the glass slab?

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Answer 1

Answer:

we know that refractive index n=

$\frac{speedoflightinmedium</p><p>}{speedoflightinvacuum}$

where c=3×10

8

m/s

1.5=

v

c

v=

1.5

3×10

8

v=2×10

8

m/s

For critical angle we will use snell's law

C is critical angle

n

glass

sinC=n

air

sin90 n

air

=1

sinC=

n

glass

1

=

1.5

1

C=41.8

o