Question

1. which color on the visible spectrum is slowed least by a glass prism? yellow blue red violet

Explanation:

When light passes through a glass prism, different colors (wavelengths) are refracted (bent) by different amounts. The refractive index of a material (glass in this case) is inversely related to the wavelength of light. Red light has the longest wavelength among the given options (yellow, blue, red, violet). A longer - wavelength light is slowed down (refracted) less by the prism. This is because the refractive index \(n\) of a medium for light of wavelength \(\lambda\) is such that \(n\) decreases as \(\lambda\) increases (for a given medium). Mathematically, the refractive index \(n\) and the speed of light \(v\) in the medium are related by \(n=\frac{c}{v}\), where \(c\) is the speed of light in vacuum. So, a lower refractive index (for longer - wavelength light like red) means a higher speed (less slowing down) in the medium.

Answer:

C. red