When light travels from glass to air, several properties of the electromagnetic (EM) wave can be observed. Here are some key aspects:
Refraction: The EM wave undergoes refraction at the interface between the glass and air. Refraction is the bending of light as it passes from one medium to another with different optical properties. In this case, the change in the optical density between glass and air causes the light to change direction.
Change in Velocity: As the light enters air from glass, its velocity changes. Light travels slower in glass than in air due to the difference in the refractive indices of the two materials. When light passes from a medium with a higher refractive index (such as glass) to one with a lower refractive index (such as air), its velocity increases.
Change in Wavelength: The wavelength of the EM wave also changes when it passes from glass to air. The wavelength is inversely proportional to the refractive index of the medium. Since air has a lower refractive index than glass, the wavelength of the light increases as it transitions from glass to air.
Change in Frequency: The frequency of the EM wave remains constant during the transition from glass to air. According to the wave equation, the product of wavelength and frequency is constant for a given wave. Therefore, as the wavelength increases, the frequency must decrease to maintain the constant product.
Partial Reflection and Transmission: When light encounters the interface between glass and air, a portion of the light is reflected back into the glass while the remaining portion is transmitted into the air. The amount of reflection and transmission depends on the angle of incidence and the properties of the materials involved.
It's worth noting that these observations are based on the assumption of a smooth interface and the absence of other factors such as absorption or scattering. Additionally, the properties of the EM wave can vary depending on the specific characteristics of the glass and air involved, including their refractive indices, composition, and any coatings or impurities present.