Red-shift (physics Only) (GCSE Physics)

If a galaxy shows spectral lines shifted to longer wavelengths, and another galaxy shows the same lines shifted to shorter wavelengths, what do these observations indicate?

Which discovery about spectral line patterns in distant galaxies (same pattern but shifted) was crucial to concluding galaxies contain the same chemical elements as Earth?

A galaxy’s observed spectral line is at 550 nm while the rest line is 500 nm. Which expression yields the galaxy’s recession velocity v (non-relativistic approximation)?

Which observation provides direct evidence that the Universe is expanding?

A spectral absorption line has rest wavelength 500.0 nm. In a galaxy it is observed at 505.0 nm. What is the redshift z?

Hubble’s law relates a galaxy’s recessional velocity v to its distance d by v = H0 d. Which statement about H0 (Hubble constant) is correct?

Relativistic formula for redshift is needed when z is large. Which approximation is commonly used for small z (e.g., z « 1)?

An observed spectral line has rest 450.0 nm, observed 472.5 nm. Calculate z and state whether the galaxy is approaching or receding.

Which of the following would produce a blueshift rather than a redshift for a star’s spectral lines?

A student measures ?rest = 520 nm and ?obs = 572 nm. Using z = ??/?rest, find z and explain what it implies.

If redshift measurements show all galaxies are moving away from us, does that mean we are at the centre of the Universe?