Question

| 10. What should be the value of refractive index nofa glass
rod placed in air, so that the light entering through the flat
surface of the rod does not cross the curved surface of
the rod?
Glass
Fig. 1.170​

Answer 1

Answer:

n>√2

Explanation:

It is required that no ray exits from the curved surface.

This will be automatically fulfilled if minimum r' is more than critical angle.

Angle r' is minimum when r is maximum ie C.

Therefore minimum value of r' is 90−c

From above condition

90∘−C>C

or C<45∘

sinC<sin45∘

1n<12–√

n>2–√