Dispersion due to wavelength-dependent refraction

Steps:

• White light splits in a prism because shorter wavelengths (blue) refract more than longer ones (red).
• Refractive index $n = c/v$ is higher for blue light, meaning blue slows down more in glass.
• Red light, with lower $n$, travels faster in the prism (slowed less).
• Less slowing for red results in less bending (refraction) per Snell's law.

Why A is correct:

• Red light has lower refractive index than blue, so it slows less ($v$ closer to $c$) and bends less at interfaces, per $n(\lambda)$ variation in dispersive media.

Why the others are wrong:

• B: Red is not slowed more; it has lower $n$.
• C: Red is neither slowed more nor refracted more; opposite is true.
• D: Red is not refracted more; it deviates less.

Final answer: A