Red-shift (physics Only) (GCSE Physics)

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?

Two identical spectral lines have rest wavelength 400 nm. In galaxy A the line is at 420 nm, in galaxy B at 440 nm. Which galaxy is farther away assuming Hubble’s law applies?

Which observation provides direct evidence that the Universe is expanding?

A star’s spectral lines are observed at longer wavelengths than in a laboratory. This shift is called red-shift because the light is shifted towards which part of the spectrum?

Why do the dark lines in the spectrum of a distant galaxy match the same pattern of lines in the Sun’s spectrum even though the lines are shifted?

Explain why a photon emitted at ultraviolet wavelengths long ago may now be observed as visible or infrared light due to redshift.

Using the non-relativistic approximation v ˜ z c (where c = 3.00 × 10^8 m/s), what is the recessional velocity of a galaxy with z = 0.010?

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

How does observing redshift from many galaxies in all directions support the cosmological principle (that the Universe is homogeneous and isotropic on large scales)?

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 of the following best describes what a positive redshift (z > 0) of a galaxy’s light indicates?