**Correct Option: B. The light slows down and bends towards the normal.** ### Detailed Explanation: When light travels from one medium to another, such as from air (a less dense medium) into water (a denser medium), it undergoes a phenomenon known as refraction. Refraction is the bending of light as it passes from one medium to another due to a change in its speed. 1. **Change in Speed:** - Light travels at different speeds in different media. In air, light travels at approximately 3.00 x 10^8 meters per second. However, when light enters water, which is denser than air, its speed decreases. The speed of light in water is about 2.25 x 10^8 meters per second. - This decrease in speed is due to the interaction of light with the molecules in the water, which causes the light to take longer to pass through the medium. 2. **Change in Direction:** - As light slows down when entering a denser medium, it also changes direction. The direction of the light ray bends towards the normal line, which is an imaginary line perpendicular to the surface at the point of incidence (where the light enters the water). - The bending of light towards the normal occurs because of Snell's Law, which states that: \[ n_1 \sin(\theta_1) = n_2 \sin(\theta_2) \] where: - \( n_1 \) is the refractive index of the first medium (air, approximately 1.00), - \( n_2 \) is the refractive index of the second medium (water, approximately 1.33), - \( \theta_1 \) is the angle of incidence (the angle between the incoming light ray and the normal), - \( \theta_2 \) is the angle of refraction (the angle between the refracted light ray and the normal). - Since the refractive index of water is greater than that of air, the sine of the angle of refraction (\( \theta_2 \)) must be smaller than the sine of the angle of incidence (\( \theta_1 \)), indicating that \( \theta_2 < \theta_1 \). This means the light bends towards the normal. ### Why Other Options Are Incorrect: - **Option A: The light speeds up and bends away from the normal.** - This option is incorrect because when light enters a denser medium (like water), it actually slows down, not speeds up. Additionally, light bends towards the normal when entering a denser medium, not away from it. - **Option C: The light speeds up and continues in a straight line.** - This option is also incorrect. Light does not speed up when entering a denser medium; it slows down. Furthermore, it does not continue in a straight line; it bends due to refraction. - **Option D: The light slows down and bends away from the normal.** - This option is misleading. While it correctly states that the light slows down, it incorrectly states that the light bends away from the normal. In fact, it bends towards the normal when entering a denser medium. ### Summary of Key Points: - Light slows down when it enters a denser medium (from air to water). - Light bends towards the normal line when it refracts into a denser medium. - Snell's Law describes the relationship between the angles of incidence and refraction and the refractive indices of the two media. - Understanding the behavior of light during refraction is crucial for applications in optics, such as lenses and prisms.