Tag: spectra

Quizzes (2) Questions (122)

Questions Related to spectra

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.

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

The sky appears blue due to:

  1. reflection of light

  2. dispersion and scattering of light

  3. total internal reflection of light

  4. blue colour of water droplets
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The sky appears blue due to dispersion and scattering of white light from the Sun and the blue color scatters the most because of its small wavelength as compared to other colors in spectrum.

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

The splitting of white light into its colored components is called _____.

  1. Spectrum

  2. Dispersion

  3. Deviation

  4. Refraction
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The prism splits the incident light beam into a band of 7 colors. This band of colored components of a light beam is called its spectrum and the phenomenon of splitting of light into its component colours is called dispersion.

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

When white light passes through a dispersive medium, it breaks up into various colours. Which of the following is true?

  1. Velocity of light for violet is greater than the velocity of light for red colour

  2. Velocity of light for violet is less than the velocity of light for red

  3. Velocity of light is the same for all colours

  4. Velocity of light for different colours
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When light falls on the glass prism, refraction takes place. Since the wavelength of different components of light is different and the frequency is constant, each component gets deviated by a different angle due to the difference in velocity in the glass medium. The red color having the maximum wavelength and velocity, deviates the least and forms the upper part of the spectrum whereas violet having the least wavelength and velocity deviates the most.