When a wave travels from a slower medium to a faster medium, the refracted ray bends in which direction relative to the normal?

When a wave travels from a slower medium to a faster medium, the refracted ray bends in which direction relative to the normal?

• A. It bends toward the normal
• B. It bends away from the normal
• C. It remains at the same angle
• D. It disappears

Answer: (B)

When light moves from a slower medium to a faster medium, its speed increases in the second medium, and the refracted ray bends away from the normal. This follows Snell’s law, which says n1 sin(theta1) = n2 sin(theta2). Since the first medium has a higher refractive index (slower light) than the second, n1 > n2, so sin(theta2) = (n1/n2) sin(theta1) is greater than sin(theta1). That makes theta2 larger than theta1, meaning the refracted ray sits at a larger angle relative to the normal. In short, the ray bends away from the normal when entering a faster medium. (If the incident angle is large enough, total internal reflection can occur, but that’s beyond the basic bending behavior.)

When light moves from a slower medium to a faster medium, its speed increases in the second medium, and the refracted ray bends away from the normal. This follows Snell’s law, which says n1 sin(theta1) = n2 sin(theta2). Since the first medium has a higher refractive index (slower light) than the second, n1 > n2, so sin(theta2) = (n1/n2) sin(theta1) is greater than sin(theta1). That makes theta2 larger than theta1, meaning the refracted ray sits at a larger angle relative to the normal. In short, the ray bends away from the normal when entering a faster medium. (If the incident angle is large enough, total internal reflection can occur, but that’s beyond the basic bending behavior.)