Question

20. A monochromatic light passes through a glass slab (u = 3/2) of thickness 9 cm in time ty. If it
takes a time t2 to travel the same distance through water ( u = 4/3). The value of (t1 - tz) is
2.5 x 10-11
3.2.5 x 10-10
4.5 x 10-10
1. 5 x 10-8
S​

Answer 1

Answer:

Answer

C→ Speed of light in vacuum

V→ Speed of light in medium 

Refractive Index,

μ=C/V

time=distance/speed

μ1=3/2(Glass)

V1=μ1C1=3/23×108=2×108m/s

d=90cm=0.9m

t1=d/V1=0.9m/2×108m/s

t1=0.45×10−8s

μ2=4/3(water)

V2=μ2C1=4/33×108m/s=2.25×108m/s

d=90cm=0.9m

t2=v2d=0.25×108m/s0.9 

t2=0.4×10−8s

t1−t2=0.45×10−8s−0.40×10−8=0.05×10−8s

t1−t2=5×10−10s