The velocities of light in air and glass are 3.0 x 108ms-1 and 2.0 x 108ms-1 respectively. If the angle of refraction is 30^\circ, the sine of the angle of incidence is
A
0.33
B
0.50
C
0.67
D
0.75
Verified Correct Answer: D.
Step-by-Step Mathematical Solution
Refractive index
= \(\frac{Sin i}{Sin r}\) = \(\frac{\text{Vel. of light in air}}{\text{vel. of light in glass}}\)
= \(\frac{Sin i}{Sin 30^o}\)= \(\frac{3.0 \times 10^8}{2.0 \times 10^8}\)
= Sin i = \(\frac{(3.0 \times 10^8 \times Sin 30^o)}{2.0 \times 10^8}\)
= Sin i = \(\frac{(3.0 \times 10^8 \times 0.5)}{2.0 \times 10^8}\)
= \(\frac{1.5}{2}\)
= 0.75
Source: Myschool Past Questions Archive (Record #589)