Question

White light moves through a prism and separates into colors in the following order: red, orange, yellow, green, blue, and violet.
Which of the following choices correctly describes why the violet ray is at the bottom while the red ray is at the top?

Red and violet light move at the same speed but have different wavelengths, so they refract at different angles due to their different wavelengths.

Red and violet light move at the same speed but have different frequencies, so they refract at different angles due to their different frequencies.

Red light moves slowest through glass while violet light moves fastest through glass compared to other visible light. So violet and red refract at different angles.

Violet light moves slowest through glass while red light moves fastest through glass compared to other visible light. So violet and red refract at different angles.

Answer 1

Violet light moves slowest through glass while red light moves fastest through glass compared to other visible light. So violet and red refract at different angles.

Explanation:

Violet travels the slowest so it is on the bottom and red travels the fastest so is on the top. This is because what is called the index of refraction, (the ratio of the speed of light in a vacuum to the speed of light in a material), is increased for the slower moving waves (i.e. violet).