When light of wavelength `lamda_0` in vaccum travels through same thickness t in glass and water, the difference in the number of waves is _____. (Refractive indicates of glass and water are `mu_g and mu_w` respectively).

Explanation

To solve the problem, we need to find the difference in the number of waves when light of wavelength \( \lambda_0 \) in vacuum travels through the same thickness \( t \) in glass and water.

### Step-by-step Solution:

1. **Understanding the Concept of Refractive Index**:
The refractive index \( \mu \) of a medium is defined as the ratio of the speed of light in vacuum to the speed of light in that medium. It can also be expressed in terms of wavelength:
\[
\mu = \frac{\lambda_0}{\lambda}
...