MCQ Detailed View

When light passes through a prism, it undergoes refraction, bending at the surfaces of the prism due to the change in medium from air to glass. However, different colors (wavelengths) of light are refracted by different amounts because the refractive index of glass varies with wavelength—a phenomenon called dispersion.

Among visible light, red light has the longest wavelength (~700 nm), while violet has the shortest (~400 nm). In a prism, shorter wavelengths bend more than longer wavelengths, meaning violet light is deviated the most and red light is deviated the least. This principle is why white light spreads into a spectrum of colors (rainbow) when passing through a prism.

Other options are incorrect because:

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  Blue and violet are shorter wavelength colors and are deviated more than red.

  
  


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  Green has a medium wavelength and bends more than red but less than violet.

  
  

Understanding which color bends the least is important in optics, physics experiments, and spectroscopy. It also helps explain phenomena like rainbows, light dispersion in lenses, and the working of spectrometers. Red light’s minimal deviation makes it useful in alignment lasers, fiber optics, and experiments requiring low dispersion.

In summary, the correct answer is Red, as it deviates the least when passing through a prism due to its longer wavelength and lower refractive index in glass compared to other visible colors.