Radio waves travel in air at 3.0 x 108ms-1. If the waves enter water of refractive index \(\frac{4}{3}\), calculate the speed of radio waves in water
A
4.33 x 108ms-1
B
4.00 x 108ms-1
C
2.25 x 108ms-1
D
1.33 x 108ms-1
Verified Correct Answer: C.
Physical Principles & Numerical Solution
\(_an_w = \frac{4}{3} = \frac{\text{speed of light in air}}{\text{speed of light in water}}\)
\(\frac{4}{3} = \frac{3 \times 10^8}{x}\)
x = \(\frac{9 \times 10^4}{4}\)
= 2.25 x 108m/s
Source: Myschool Past Questions Archive (Record #34517)