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Question 17N.3.SL.TZ0.13

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Date November 2017 Marks available [Maximum mark: 3] Reference code 17N.3.SL.TZ0.13
Level SL Paper 3 Time zone TZ0
Command term Determine, Outline Question number 13 Adapted from N/A
13.
[Maximum mark: 3]
17N.3.SL.TZ0.13

The collision of two galaxies is being studied. The wavelength of a particular spectral line from the galaxy measured from Earth is 116.04 nm. The spectral line when measured from a source on Earth is 115.00 nm.

(a)

Outline one reason for the difference in wavelength.

[1]

Markscheme

galaxies are moving away

OR

space «between galaxies» is expanding

Do not accept just red-shift

(b)

Determine the velocity of the galaxy relative to Earth.

[2]

Markscheme

« Δ λ λ = »  1.04 115 = v c

0.009c

Accept 2.7×106 «m s–1»

Award [0] if 116 is used for  λ

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