When you shine a flashlight on glass, several phenomena occur due to the interaction between light and the glass material. The specific behavior of light when it encounters glass is primarily influenced by the optical properties and structure of glass.
Reflection: Some of the incident light is reflected off the surface of the glass. This is why you can see your reflection when you shine a flashlight on a glass surface.
Refraction: A significant phenomenon when light encounters glass is refraction. Refraction refers to the bending of light as it passes from one medium (such as air) to another (such as glass) with a different optical density. Glass has a higher refractive index than air, which causes light to change direction when it enters the glass. This bending of light is responsible for various phenomena related to glass, such as the apparent displacement of objects seen through glass, the formation of rainbows, and the focusing ability of lenses.
Transmission: Glass is a transparent material, meaning it allows light to pass through it. When light encounters glass, a portion of it is transmitted through the material. The amount of light transmitted depends on factors such as the thickness and quality of the glass, as well as the wavelength of the incident light.
Absorption: In some cases, glass can absorb certain wavelengths of light. This absorption occurs when the energy of the incident light matches the energy levels of electrons in the glass material. The absorbed energy is converted into internal energy, leading to a warming effect in the glass.
The behavior of light when shining on glass differs from other materials primarily due to the properties of transparency and refraction. Glass has a higher transparency compared to many other materials, allowing light to pass through it with minimal absorption or scattering. Moreover, its refractive index is relatively high, causing a noticeable bending of light rays as they enter and exit the glass. These properties make glass particularly useful in applications such as windows, lenses, and optical fibers.