The absolute refractive indices of glass and water are \(\frac{3}{2}\) and \(\frac{4}{3}\) respectively. The refractive index at the interface when a ray travels from water to glass is
A
\(\frac{1}{2}\)
B
\(\frac{8}{9}\)
C
\(\frac{9}{8}\)
D
\(\frac{17}{12}\)
E
2
Verified Correct Answer: C.
Physical Principles & Numerical Solution
Ray travelling from water to glass;
\(\frac{\text{speed of light in air}}{\text{speed of light in glass}}\) = \(\frac{3}{2}\)
= 3 x 108ms-1
X = 2 x 108ms-1
\(\frac{\text{speed of light in air}}{\text{speed of light in water}}\) = \(\frac{4}{3}\)
= \(\frac{3 \times 10^8}{g}\)
Y = 2.25 x 108ms-1
from water to glass;
Refractive = \(\frac{\text{speed of light in water}}{\text{speed of light in glass}}\)
= \(\frac{2.25 \times 10^8}{2.00 \times 10^8}\)
= 1.125
= \(\frac{9}{8}\)
Source: Myschool Past Questions Archive (Record #29012)