**Answer:**

The total number of wavelength is 35180.

**Explanation:**

**Given that,**

Thickness = 2.50 mm

Index of refraction =1.40

Wavelength = 540 nm

Distance = 1.80 cm

**We need to calculate the wavelength in the medium**

**Using formula of wavelength**

**We need to calculate the number of wavelength**

**Using formula for number of wavelength**

Put the value into the formula

**We need to calculate the distance traveled by light in air**

**Using formula for distance**

Put the value into the formula

**We need to calculate the number of wavelength**

**Using formula for number of wavelength**

Put the value into the formula

**We need to calculate the total number of wavelength**

Put the value into the formula

**Hence, The total number of wavelength is 35180.**