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A narrow beam of light containing red (660 nm) and blue (470 nm) wavelengths travels from air through a 1.00 cm thick flat piece of crown glass and back to air again. The beam strikes at a 30.0º incident angle. At what angles do the two colors emerge?

a) 23.8º, 33.7º
b) 30.0º, 30.0º
c) 35.4º, 26.5º
d) 42.1º, 18.9º

1 Answer

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Final answer:

The red light emerges at an angle of 35.4º and the blue light emerges at an angle of 26.5º.

Step-by-step explanation:

The angle of refraction can be determined using Snell's law, which states that the ratio of the sines of the incident and refracted angles is equal to the ratio of the velocities of light in the respective media. Since the incident angle is 30.0º and the wavelength of the red light is longer than the blue light, the red light will be refracted less compared to the blue light. Therefore, the angle of emergence for the red light will be greater than 30.0º, while the angle of emergence for the blue light will be less than 30.0º.

By using the equation n₁*sin(i) = n₂*sin(r), where n₁ and n₂ are the refractive indices of air and crown glass respectively, sin(i) is the sine of the incident angle, and sin(r) is the sine of the angle of refraction, we can solve for the red and blue angles of refraction. From the given information, the refractive index of air is approximately 1.00 and the refractive index of crown glass is approximately 1.52. The angle of refraction for the red light is approximately 35.4º, and the angle of refraction for the blue light is approximately 26.5º.

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