State Hubble’s law in words or symbols.
A star in a distant galaxy has its emission peak at a wavelength of $4.62 \times 10^{-7}\ \text{m}$. When the galaxy is observed from Earth, the star’s maximum emission is found at $4.91 \times 10^{-7}\ \text{m}$.
Explain the reason that the observed wavelength and the emitted wavelength are not the same.
Calculate the star’s speed relative to Earth.
The wavelength of maximum emission is used to find the surface temperature of the star. Explain how the temperature found from the observed wavelength compares with the true temperature found from the emitted wavelength.
The Hubble constant has the value $2.3 \times 10^{-18}\ \text{s}^{-1}$. Use your answer in (b)(ii) to find the distance from Earth of the star in (b).