The correct option is **B. The speed of light decreases and it bends toward the normal.** ### Detailed Explanation: 1. **Understanding Refraction**: - Refraction is the bending of light as it passes from one medium to another. This bending occurs because light travels at different speeds in different materials. 2. **Speed of Light in Different Media**: - In air, light travels at its maximum speed, approximately \(3.00 \times 10^8\) meters per second. However, when light enters a denser medium like water, its speed decreases. The speed of light in water is about \(2.25 \times 10^8\) meters per second. 3. **Normal Line**: - The "normal" is an imaginary line that is perpendicular to the surface at the point of incidence (where the light hits the water). When light enters water at an angle, it will either bend toward or away from this normal line depending on the relative speeds of light in the two media. 4. **Snell's Law**: - The relationship between the angles of incidence and refraction can be described by Snell's Law, which states: \[ n_1 \sin(\theta_1) = n_2 \sin(\theta_2) \] 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 at which light hits the water), - \(\theta_2\) is the angle of refraction (the angle at which light travels in water). 5. **Bending Toward the Normal**: - When light moves from a less dense medium (air) to a denser medium (water), it slows down. According to Snell's Law, since the speed of light decreases, the angle of refraction (\(\theta_2\)) will be smaller than the angle of incidence (\(\theta_1\)). This means the light bends toward the normal. ### Why Other Options Are Incorrect: - **Option A**: "The speed of light increases and it bends away from the normal." - This is incorrect because light does not speed up when entering a denser medium; it slows down. Therefore, it cannot bend away from the normal. - **Option C**: "The speed of light remains constant and it travels in a straight line." - This is incorrect because the speed of light changes when it enters a different medium. It does not remain constant, and it does not travel in a straight line when it crosses the boundary between air and water at an angle. - **Option D**: "The speed of light decreases and it bends away from the normal." - This is incorrect because while it is true that the speed of light decreases when entering water, it does not bend away from the normal; it bends toward the normal instead. ### Summary for Revision: - Light slows down when it enters a denser medium (like water) from a less dense medium (like air). - The bending of light is described by Snell's Law, which shows that the angle of refraction is less than the angle of incidence when moving into a denser medium. - Light bends toward the normal when it slows down, and this is a key concept in understanding refraction. - Remember that the refractive index is higher for denser materials, which affects the speed of light and the angle at which it refracts.