Home
Class 12
PHYSICS
It is believed that the universe is expa...

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 wavelength

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 wavelength

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question regarding the light from distant stars that are receding from us due to the expansion of the universe, we can follow these steps: ### Step-by-Step Solution: 1. **Understanding the Concept of Redshift**: - When an object emitting light is moving away from an observer, the light waves are stretched, leading to an increase in wavelength and a decrease in frequency. This phenomenon is known as redshift. 2. **Identifying the Options**: - The question provides four options regarding the behavior of light from receding stars: 1. Shift in frequency towards longer wavelength 2. Shift in frequency towards shorter wavelength 3. No shift in frequency but a decrease in intensity 4. A shift in frequency sometimes towards longer, sometimes towards shorter wavelength 3. **Analyzing the Movement of Stars**: - Since the stars are receding from us, we expect the light they emit to experience redshift. This means that the frequency of the light will decrease (or shift towards longer wavelengths). 4. **Considering Intensity**: - As the distance from the star increases (due to it receding), the intensity of light reaching us will also decrease. This is because intensity is inversely proportional to the square of the distance from the source. 5. **Conclusion**: - Based on the analysis, the light from distant stars that are receding will show a shift in frequency towards longer wavelengths (redshift) and a decrease in intensity. However, the question specifically asks for the shift in frequency. 6. **Selecting the Correct Option**: - The correct answer is: **Shift in frequency towards longer wavelength**. ### Final Answer: The light from such a star will show a **shift in frequency towards longer wavelength**. ---
Promotional Banner

Topper's Solved these Questions

  • WAVE OPTICS

    AAKASH INSTITUTE ENGLISH|Exercise Assignment (Section-B (objective type question(one option is correct)))|5 Videos

  • WAVE OPTICS

    AAKASH INSTITUTE ENGLISH|Exercise Assignment (Section-C (objective type question(More than one option are correct)))|5 Videos

  • WAVE OPTICS

    AAKASH INSTITUTE ENGLISH|Exercise Try yourself|24 Videos

  • UNITS AND MEASUREMENTS

    AAKASH INSTITUTE ENGLISH|Exercise ASSIGNMENT (SECTION - D)|15 Videos

  • WAVES

    AAKASH INSTITUTE ENGLISH|Exercise ASSIGNMENT ( SECTION-D ( Assertion - Reason Type Questions ))|12 Videos

Similar Questions

Explore conceptually related problems

Light energy emitted by star is due to

Faint band of stars observed in the night sky from north to south direction is

The small dense stars rotate about their common centre of mass as a binary system, each with a period of 1 year. One star has mass double than that of the other, while mass of the lighter star is one-third the mass of the Sun. The distance between the two stars is r and the distance of the earth from the Sun is R , find the relation between r and R .

Two stars of mass M_(1) & M_(2) are in circular orbits around their centre of mass The star of mass M_(1) has an orbit of radius R_(1) the star of mass M_(2) has an orbit of radius R_(2) (assume that their centre of mass is not acceleration and distance between starts is fixed) (a) Show that the ratio of orbital radii of the two stars equals the reciprocal of the ratio of their masses, that is R_(1)//R_(2) = M_(2)//M_(1) (b) Explain why the two stars have the same orbital period and show that the period T=2pi((R_(1)+R_(2))^(3//2))/(sqrt(G(M_(1)+M_(2)))) .

Light emitted from a distant star is observed at frequency 5000 MHz for the star stationary with respect to us. If the star starts approaching us with speed 6xx10^(5)m//s . Then the observed frequency will be

In astronomical observations, signals observed from the distant stars are generally weak. If the photon detector receives a total of 3.15xx10^(-18)J from the radiations of 600 nm , calculate the number of photons received by the detector.

In astronomical observations, signals observed from the distant stars are generally weak If the photon detector receives a total of 3.15 xx 10^(-18) J from the radiations of 600 nm, calculate the number of photons received by the detector.

Although a photon has no rest mass, but it possesses the inertial mass m="hf"/c^2 where h is Planck's constant , f is frequency of light and c is speed of light . Since light is deflected by a gravitational field , so it is naturally assured that photons have same gravitational behaviour as other particles. When photon is emitted from source of star of mass M and radius R, total energy of photon will be sum of hf and gravitational potential energy. At a large distance from star, the photon is beyond the star's gravitational field , so its gravitational potential energy becomes zero but its total energy remains constant. So frequency of a photon emitted from surface of a star decreases as it moves away from star. A photon in visible region of spectrum is thus shifted towards red end, and this phenomena is known as gravitational red shift. The potential energy of photon which is at surface of star is (where , M=Mass of the star , R=Radius of the star, G=Universal gravitational constant )

A(nonrotating) star collaps onto from an initial radius R_(i) with its mass remaining unchanged. Which curve in figure best gives the gravitational acceleration a_(g) on the surface of the star as a function of the radius of the star during the collapse?

AAKASH INSTITUTE ENGLISH-WAVE OPTICS-Assignment (Section-A (objective type question(one option is correct)))
  1. If a torch is used in place of monochromatic light in Young's experime...

    Text Solution

    |

  2. In Young's double slit experiment when two light waves form third mini...

    Text Solution

    |

  3. It is believed that the universe is expanding and hence the distant st...

    Text Solution

    |

  4. The 6563 Ã… H(alpha) line emitted by hydrogen in a star is found to be...

    Text Solution

    |

  5. In the context of Doppler effect in light, the term red shift signifie...

    Text Solution

    |

  6. A slit of width a is illuminated by white light. The first minimum for...

    Text Solution

    |

  7. The bending of light about corners of an obstacle is called

    Text Solution

    |

  8. Angular width (beta) of central maximum of a diffraction pattern on a ...

    Text Solution

    |

  9. Red light is generally used to observe diffraction pattern from single...

    Text Solution

    |

  10. When a compact disc is illuminated by a source of white light, coloure...

    Text Solution

    |

  11. For what distance is ray optics a good approximation when the aperture...

    Text Solution

    |

  12. To observe diffraction, the size of the obstacle

    Text Solution

    |

  13. In a single slit diffraction pattem

    Text Solution

    |

  14. Diffraction and interference of light refers to -

    Text Solution

    |

  15. A polariser in used to

    Text Solution

    |

  16. Light waves can be polarides as they are

    Text Solution

    |

  17. Through which character, we can distinguish the light waves form sound...

    Text Solution

    |

  18. The angle of polarisation for any medium is 60^(@) , what will be crit...

    Text Solution

    |

  19. Which of the following cannot be polarised?

    Text Solution

    |

  20. An unpolarised light of intensity Io is passed through a polaroid. The...

    Text Solution

    |