The 6563 Å H(2) line emitted by hydrogen...

The `6563 Å H_(2)` line emitted by hydrogen in a star is found to be red shifted by `15 Å`. Estimate the speed with which the star is receding from earth.

Text Solution

Verified by Experts

Given, Red shift , `lambda. - lambda = 15 Å = 15 xx 10^(-10) m`
Wavelength of `H_(alpha)`, line, `lambda = 6563 Å = 6563 xx 10^(-10) m`
Speed of the receding star, `upsilon` = ?
As the star is receding away, `upsilon` will be negative
Since `lambda. - lambda` is positive,
`lambda. - lambda = - (upsilon lambda)/c`
`implies upsilon = -(c(lambda. - lambda))/(lambda)`
or ` upsilon = -(3 xx 10^8 xx 15 xx 10^(-10))/(6563 xx 10^(-10))`
`= - 6.86 xx 10^(5) m s^(-1)`

Topper's Solved these Questions

WAVE OPTICAL
MODERN PUBLICATION|Exercise NCERT (EXemplar Problems Obejective Questions) (Multiple Choice Questions (Type-I)|5 Videos
WAVE OPTICAL
MODERN PUBLICATION|Exercise NCERT (EXemplar Problems Obejective Questions) (Multiple Choice Questions (Type-II)|4 Videos
WAVE OPTICAL
MODERN PUBLICATION|Exercise NCERT FILE SOLVED (TEXT BOOK EXERCISES)|10 Videos
SEMICONDUCTOR ELECTRONICS METERIALS DEVICES AND SIMPLE CIRCUITS
MODERN PUBLICATION|Exercise CHAPTER PRACTICE TEST FOR BOARD EXAMINATION|12 Videos

The 6563 Å line emitted by hydrogen atom in a star is found to be red shifted by 5 Å. The speed with which the star is receding form the earth is

`17.29xx10^(9) m//s`

`4.29xx10^(7) m//s`

`3.39xx10^(5) m//s`

`2.29xx10^(5) m//s`

The 6000Å line emitted by a gaseous element in a star iis found to have red shift of 15Å . What is the speed with which the star is receding from the earth ? (c=3 xx 10^(8) m//s )

`5xx10^(5) m//s `

`6xx10^(5) m//s `

`7.5xx10^(5) m//s `

`9xx10^(5) m//s `

The speactral line emitted by a star, has a wavelength of 6800 Å when observed form a Speed of star in the line of light relative to earth for receding or approach is given by

`2.42 xx 10^5 ms^(-1)` receding

`4.64 xx 10^6 ms^(-1)` receding

`6.86 xx 10^6 ms^(-1)` receding

`8.70 xx 10^5 ms^(-1)` receding