Light of frequency 5×10^4 is travelling in a medium of refractive index 1.5. What is the wavelength?

1 Answer
Apr 15, 2018

\lambda=\frac{c}{nf}=4000m

Explanation:

Let's start with the definition of the refractive index:

n=\frac{c}{v}

v=\lambda f

Whence:

n=\frac{c}{\lambda f}\implies \lambda=\frac{c}{nf}

Now we can simply use the values we're given to calculate the wavelength (assuming that the speed of light is 300 million meters per second):

\lambda=\frac{3\cdot 10^8}{5\cdot 10^4\cdot 1.5}=4000m