Home
Class 12
PHYSICS
How does the red shift confirm that the ...

How does the red shift confirm that the universe is expanding?

A

Wavelength of light emitted by galaxies appears decrease

B

Wavelength of light emitted by galaxies appears to increase

C

Wavelength of light emitted by galaxies appears to be the same

D

None of the above

Text Solution

Verified by Experts

The correct Answer is:
B
According to Doppler's effect whenever there is a relative motion between a source of light and an observer, the apparent frequency of light received by observer, is different from the true frequency of light emitted by the source. When the distance between the source (galaxy) and observer is increasing, the apparent frequency is decreased and wavelength is increased, i.e., there is a shifting towards red end of the spectrum. Hence, we conclude that universe is expanding.
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • WAVE OPTICS

    A2Z|Exercise Assertion Reason|16 Videos

  • WAVE OPTICS

    A2Z|Exercise Section D - Chapter End Test|29 Videos

  • WAVE OPTICS

    A2Z|Exercise AIPMT/NEET Questions|22 Videos

  • SOURCE AND EFFECT OF MAGNETIC FIELD

    A2Z|Exercise Section D - Chapter End Test|30 Videos

Similar Questions

Explore conceptually related problems

How is the universe formed?

What does a rightward shift indicate?

Knowledge Check

  • Red shift means

    A
    Source is going away from observer
    B
    Source is coming towards observer
    C
    There is no relative motion between observer & source
    D
    None of these

  • Red shift' confirms the theory of expanding universe by using

    A
    Stefan's law
    B
    Wien's law
    C
    Doppler's effect in light
    D
    Kirchhoff's law

  • It is believed that the universe is expanding and hence the distant stars are receding from us. Light from such a star will show

    A
    Shift in frequency towards longer wavelengths
    B
    Shift in frequency towards shorter wavelength
    C
    No shift in frequency but a decrease in intensity
    D
    A shift in frequency sometimes towards longer and sometimes towards shorter wavelengths

    • Similar Questions

    Explore conceptually related problems

    When does a PPF shift to the right ?

    Why does he say that the redness of the fire is cruel?

    In a slum area, many people are reported to be suffering from malaria. Mention the unhygienic conditions that must be prevailing there. How does a doctor confirm malaria ? List various preventing measures of malaria.

    Given below are two statements: Assertion (A): Universe is expanding. Reason (R): The result is based on red shift of spectra of galaxies.

    A solution turns methyl orange red. It can turn the universal indicator to _____

    Home
    Profile