As an expert in the field of physics, particularly in the area of optics, I can explain the phenomenon that occurs when light transitions from one medium to another, such as from air into glass.

When light travels from air into glass, it undergoes a process known as refraction. Refraction is the change in direction of a wave when it passes from one medium to another, which happens because the speed of light varies in different media. The speed of light in a vacuum is a constant, denoted by \( c \), approximately \( 3 \times 10^8 \) meters per second. However, when light enters a medium like air or glass, its speed decreases due to the interaction with the atoms and molecules in the medium.

The extent to which light bends when it enters a new medium is quantified by the medium's refractive index, represented by the symbol \( n \). The refractive index is the ratio of the speed of light in a vacuum to the speed of light in the medium:

\[ n = \frac{c}{v} \]

where \( v \) is the speed of light in the medium.

When light passes from a less dense medium (like air) to a denser medium (like glass), it slows down and bends towards the normal. The normal is an imaginary line perpendicular to the surface at the point where the light enters the new medium. This bending effect is described by Snell's Law, which relates the angles of incidence and refraction to the refractive indices of the two media:

\[ n_1 \sin(\theta_1) = n_2 \sin(\theta_2) \]

Here, \( n_1 \) and \( n_2 \) are the refractive indices of air and glass, respectively, and \( \theta_1 \) and \( \theta_2 \) are the angles of incidence (the angle between the incoming light and the normal) and refraction (the angle between the refracted light and the normal), respectively.

The reference to Figure (b) in your instructions suggests an experiment where light is shone into glass at an angle. When light enters the glass at an angle, it is refracted because the refractive index of glass is higher than that of air. This means that light travels more slowly in glass than in air. As a result, the light changes direction and bends towards the normal line.

The degree of bending depends on the angle at which the light enters the glass and the difference in refractive indices between the two media. If the angle of incidence is small, the light will bend only slightly. However, if the angle of incidence is large, the light will bend more noticeably. There is a critical angle at which the refracted light will bend and run along the surface of the glass, a phenomenon known as total internal reflection.

In summary, when light goes from air into glass, it bends towards the normal due to the change in the speed of light caused by the higher refractive index of the glass. This fundamental principle of optics has numerous practical applications, from the focusing of lenses in cameras and eyeglasses to the total internal reflection in optical fibers that enable long-distance communication.

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The bending occurs because light travels more slowly in a denser medium. ... Figure (b): Shine the light into the glass at an angle. As the light enters the water, it is refracted. Since the light is passing from air (less dense) into water (more dense), it is bent towards the normal.read more >>