Physics, 08.03.2021 20:10 martinjohnsond079
Suppose that you'd like to find out if a distant star is moving relative to the earth. The star is much too far away to detect any change in its brightness as it moves toward or away from the earth. Instead we can use the Doppler effect to determine its relative speed. For this problem we are going to look at the spectral lines from hydrogen, specifically the one with a wavelength of 656.46 nm.
The hydrogen atoms in a star are also moving at high velocity because of the random motions caused by their high temperature. As a result, each atom is Doppler shifted a little bit differently, leading to a finite width of each spectral line, such as the 656.46-nm line we were just discussing. For a star like our sun, this leads to a finite width of the spectral lines of roughly Δλ=0.04nm.
If our instruments can only resolve to this accuracy, what is the lowest speed V, greater than 0, that we can measure a star to be moving?
Answers: 2
Physics, 21.06.2019 14:50
Acylindrical specimen of a nickel alloy having an elastic modulus of 207 gpa (30 × 106psi) and an original diameter of 10.2 mm (0.40 in.) experiences only elastic deformation when a tensile load of 8900 n (2000 lbf) is applied. compute the maximum length of the specimen before deformation if the maximum allowable elongation is 0.25 mm (0.010 in.)
Answers: 3
Physics, 21.06.2019 16:30
Which term best describes the phrase “something that happens”?
Answers: 3
Physics, 22.06.2019 09:00
What is a possible result of higher air temperature caused by global warming
Answers: 1
Physics, 22.06.2019 15:40
If two parallel light rays hit a mirror, they will not be parallel to each other after they reflect.
Answers: 1
Suppose that you'd like to find out if a distant star is moving relative to the earth. The star is m...
English, 25.05.2021 19:20
English, 25.05.2021 19:20
Mathematics, 25.05.2021 19:20
Mathematics, 25.05.2021 19:20
Chemistry, 25.05.2021 19:20
Mathematics, 25.05.2021 19:20
Mathematics, 25.05.2021 19:20
Mathematics, 25.05.2021 19:20