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Monday, April 30, 2018

HW answers


1      C
2      A
M3.(a)      (i)      Spectral line moved to longer wavelength position (allow ‘to red end of spectrum’)
B1



(ii)     Mention of Doppler effect
B1
Expansion of universe / Big Bang
B1
Wavelength increased (or frequency decreased)
B1
Successive ‘peaks’ of wave emitted at increasing distance
from Earth [allow ‘wave stretched’]
B1
Wavelength observed on Earth increases compared with
source stationary
B1
max 4
the use of physics terms is accurate, the answer is fluent / well argued with few errors in spelling, punctuation and grammar
B2
award for 2+
the use of physics terms is accurate, but the answer lacks coherence or the spelling, punctuation and grammar are poor
B1
award for 1
the use of physics terms is inaccurate, and the answer is disjointed with significant errors in spelling, punctuation max 2
and grammar



B0
max 2
V = c * Δf / f [or Δλ / λ] = 3 × 108 × 2.08 × 1013 / 5.556 × 1014



C1
[ecf from bi]
M1
= 1.12 × 107 m / s
A1



(iii)     [d = v / H]
conversion to km / s

C1
d = 11.2 × 103 / 65 = [172 Mpc] [ecf from bii]
B1
= 172 × 106 × 3 × 1016 = 5.17 × 1024 m
A1
[16]