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Physics
Paper 2
Question | Answer |
---|---|
Materials through which light travels more slowly, for example diamond, have a ________ refractive index | higher |
Materials through which light travels more quickly, for example water, have a ________ refractive index | lower |
Why is Cosmic Microwave Background radiation evidence of the Big Bang? | The universe is expanding and cooling from the Big Bang, which must have produced a radiation, which is why this radiation is 'cooling' and dropping in frequency |
Define redshift | The fractional increase in wavelength due to the source and observer moving away |
Explain the term galactic redshift (3) | - An increase in the observed wavelength of light emitted from distant galaxies - When compared to the wavelength of similar light on earth - Galactic redshift is evidence that the Universe is expanding |
Explain why the galactic redshift provides evidence to support the Big Bang theory (2) | - If the Universe is expanding, then it must have been closer together in the past - The expansion of the Universe can be extrapolated back to its point of origin |