When light of wavelength 5000 Å in vacuum travels through same thickness in glass and water, the difference in the number of waves is 400. Find thickness. (Refractive indices of glass and water are `(3)/(2)` and `(4)/(3)` respectively)

Explanation

To solve the problem, we need to find the thickness of the medium (glass or water) through which light of wavelength 5000 Å travels, given that the difference in the number of waves is 400. The refractive indices of glass and water are provided as \( \frac{3}{2} \) and \( \frac{4}{3} \), respectively.

### Step-by-Step Solution:

1. **Convert Wavelength to Meters:**
The wavelength of light in vacuum is given as 5000 Å (angstroms). We need to convert this to meters for our calculations.
\[
\lambda = 5000 \, \text{Å} = 5000 \times 10^{-10} \, \text{m} = 5 \times 10^{-7} \, \text{m}
...