Tag: spectra

Questions Related to spectra

The deflection of light by minute particles and molecules in all distraction is known as ____of light .

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

  1. dispersion

  2. interference

  3. diffraction

  4. scattering

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Correct Option: A

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

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

  1. $refraction$

  2. $spectrum$

  3. $dispersion$

  4. $scattering$

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Correct Option: C

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

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

  1. reflection

  2. refraction

  3. dispersion

  4. all the above

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Correct Option: C
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.

A rainbow is formed when the air is completely dry

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

  1. True

  2. False

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Correct Option: B
Explanation:

False. It is formed only after or before the rains when the air is full of moisture

A ray of light after passing through a medium were spread up into different colours. The phenomenon is called :

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

  1. Total internal reflection

  2. Diffraction

  3. Dispersion

  4. Deviation

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Correct Option: C
Explanation:

A ray of light after passing through a medium were spread up into different colours. The phenomenon is called dispersion.

Dispersion of white light into its constituent colours occurs during :

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

  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

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Correct Option: D
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.

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

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

  1. refraction

  2. reflection

  3. dispersion

  4. none of these

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Correct Option: C
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.

The sky appears blue due to:

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

  1. reflection of light

  2. dispersion and scattering of light

  3. total internal reflection of light

  4. blue colour of water droplets

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Correct Option: B
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.

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

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

  1. Spectrum

  2. Dispersion

  3. Deviation

  4. Refraction

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Correct Option: B
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.

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

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

  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

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Correct Option: B
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.