A line spectrum includes the wavelength 382 nm. When analysing light from a distant galaxy, this line is measured to be at 396 nm. Calculate the recessional speed of the galaxy in km s-1. Give the unit in the form "km s-1". Give your answer to three significant figures.

When the light from a distant galaxy is analysed, it is found that a line on its spectrum is 32 nm longer than when the same spectrum is produced on Earth. Given that the light was emitted with a wavelength of 430 nm, calculate the cosmic scale factor when it was emitted. Give your answer to 2 significant figures.

A specific spectral line from a distant galaxy has been red shifted from a wavelength of 450 nm to 762 nm. At what speed (as a fraction of c) is the galaxy receding from the Earth? No units are needed.

A distance galaxy is moving away from us at a speed of 47380367 m/s. For hydrogen gas in this galaxy, calculate the wavelength (in nm) to one decimal place of the hydrogen alpha line as observed here on earth. Note: This wavelength emitted by hydrogen is measured in the first year physics lab to be 656.2 nm.

From laboratory measurements, we know that a particular spectral line formed by hydrogen atom appears at a wavelength of 486.1 nanometers (nm). The spectrum of a particular star shows the same hydrogen line appearing at a wavelength of 485.9 nm. What can we conclude?

A star at a temperature of 8200 K is observed in a distant galaxy at redshift = 2.7.(i) Which equation relates the observed wavelength, to the actual wavelength, , emitted by the star? Select the correct option from the following.