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Multiple choice physics option c: imaging sunlight - white and coloured sunlight - combination of 7 lights fibre optics basics

The splitting of white light into several colours on passing through a glass prism is due to -

  1. Refraction

  2. Reflection

  3. Interference

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The splitting of white light into its constituent colour is called dispersion. Dispersion occurs because refraction or bending differs with the colour.

Multiple choice physics human eye and colourful world sunlight - white and coloured sunlight - combination of 7 lights fibre optics basics

What does the dispersion of light in a medium imply
i) Lights of different wavelength travel with different speeds in the medium.
ii) Light of any frequency will travel with the same speed in the medium
iii) The refractive index of the medium is different for different wavelength of light

  1. $(i)$ and $(ii)$ only
  2. $(ii)$ and $(iii)$ only
  3. $(i)$ and $(iii)$ only
  4. $(i),(ii)$ and $(iii)$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Dispersion occurs because the refractive index of a medium depends on the wavelength of light. Since refractive index is related to the speed of light in the medium (n = c/v), different wavelengths travel at different speeds, causing them to deviate by different amounts.

Multiple choice physics spectra sunlight - white and coloured sunlight - combination of 7 lights fibre optics basics

When the white light is passed through a equilateral prism it splits into seven colours. The phenomena of splitting of white light is called :

  1. $refraction$
  2. $spectrum$
  3. $dispersion$
  4. $scattering$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The splitting of white light into its seven constituent colors when passing through a prism is known as dispersion. Refraction is the bending of light, and the spectrum is the resulting band of colors.

Multiple choice physics spectra sunlight - white and coloured sunlight - combination of 7 lights fibre optics basics

The phenomenon due to which white light splits into seven colours on passing through a prism is called _________

  1. reflection

  2. refraction

  3. dispersion

  4. all the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The phenomenon due to which white light splits into seven colours on passing through a prism is called dispersion. White light is made up of seven bands of colors each having different wavelengths. Upon passing through a medium, each of the colors travels at different speeds and hence has different angles of refraction leading to the splitting of the light i.e. dispersion.

Multiple choice physics spectra sunlight - white and coloured sunlight - combination of 7 lights fibre optics basics

Dispersion of white light into its constituent colours occurs during :

  1. Reflection at a plane mirror

  2. Reflection at a concave mirror

  3. Internal reflection inside a spherical drop of water

  4. Refraction at the boundary of a transparent medium
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Answer is D.

The spectral colors of the rainbow are caused by dispersive refraction. Newton established that refraction causes the dispersion of light into its constituent colours. He named seven colors, in symmetry with the seven distinct notes in the Western musical scale.
Refraction is the bending of a light as it crosses the boundary into a different medium and it is determined by its refractive index, or how much the light is slowed down in the new medium.
Hence, dispersion of white light into its constituent colors occurs during refraction at the boundary of a transparent medium.

Multiple choice physics spectra sunlight - white and coloured sunlight - combination of 7 lights fibre optics basics

The splitting of white light into several colours on passing through a glass prism is due to

  1. refraction

  2. reflection

  3. dispersion

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
$ \bf{Refraction} $ of light is the phenomenon of bending of light or change in the direction of light, when it passes obliquely from one transparent medium to another.

$ \bf{Reflection} $ is the phenomenon in which light rays on striking a polished surface(such as a mirror) bounce back or are sent back into the same medium. 

$\bf{Dispersion} $ is the phenomenon of splitting of white light into its component colours (VIBGYOR) on passing through a glass prism.

Hence, the correct answer is OPTION C.