Question

The critical angle for total internal refraction is 45 degrees the velocity of light in that mediam is

Answer 1

For critical angle we will use snell's law

C is critical angle and C=45o

nmediumsinC=nairsin90     nair=1

sinC=SinC1=sin451

nmedium=1.41

we know that refractive index n=speedoflightinmediumspeedoflightinvacuum

where c=3×108m/s

1.414=vc

v=1.4143×108

v=2.12×108m/s

HOPE IT HELPS..............