1.	(a)	

P moving away, Q towards (1)
l increasing and decreasing respectively (1)	5
 
(b)	(i)	 (1)
= 6.5 × 107 ms–1 (1)
away from Earth (1)
 
(ii)	correct l = 4.7804(× 10–7 m) (1)
u = (1)
= 8.30 × 105 (ms–1) (1)
period T = 240 (day) (1)
r = (1)
= 2.73 ×1012m (1)	max 7
[12]
 
2.	(a)	(i)	change in (apparent) frequency [or wavelength] (1)
due to relative motion between source and observer (1)
(ii)	from spectrum obtain change in wavelength, , for a spectral line (1)
using known wavelength measured on Earth (1)
calculate u from  = (–)(1)
 
(iii)	radar or rotation of star (1)
double Doppler effect because body acts as source for return signal (1)
[for rotation, one limb moves towards Earth, one away]	max 6
 
(b)	(i)	use of u = Hd (1)
u =  = 7.5 × 105 ms–1
(ii)	=  = 1.64 × 10–9 (m) (1)
lobs = (6.5647 + 0.0164) × 10–7 = 6.58 × 10–7 m (1)	4
[10]
 
3.	(a)	(i)	 =  (1)
(ii)	 = – (1)	2
 
(b)	(i)	total difference in wavelength =  (1)
u =  = 1986[or 2.0 × 103] m s–1 (1)
 
(ii)	w =  =  (1)
= 2.8 × 10–6 rad s–1 (1)	4
[6]
 
4.	(a)	(quasars are) strong radio sources (1)	1
 
(b)	(i)	(use of  v = (–) (1)
	 = (–)1.10 × 108 ms–1 (1)
 
(ii)	(use of v = Hd gives) d =  (1) (= 1700 Mpc)	3
	(allow C.E. for value of v from (b)(i))
(c)	(i)	 (1)
 = 1012 (1)
 
(ii)	very large power (1)
large distance away or large redshift (1)
small size/star like/rapid variation (1)	max 4
	QWC
[8]

5.	main features :
	expanding Universe (from single point)  (1)
	suggest about 15 billion years ago  (1)
	‘explosion’ - creation of space/matter/time   (1)
	evidence :
	red shift of distant galaxies   (1)
	in keeping with Hubble’s law  (1)
	Hubble’s law can be used to age Universe  (1)	max 4
		QWC 2
[4]
 
6.	(a)	black hole: large gravitational field or very dense  (1)
escape velocity greater than c  (1)
quasar: large red shift or very far away  (1)
very powerful sources  (1)	max 3
	QWC 1
 
(b)	  (1)
= 8.9 × 1012m  (1)	2
[5]

7.	(a)	two stars of different brightness orbit a common axis (1)
most of the time both stars are visible, so brightness is a maximum
i.e. low value of apparent magnitude (1)
at A, when dimmer star passes in front of brighter star there is an
increase in apparent magnitude (fall in brightness) (1)
at B, (half a cycle later), the brighter star passes in front of the dimmer,
brightness falls slightly hence small increase in apparent magnitude (1)
transit time indicate different sizes (1)
width of trough indicates transit times (1)	max 4
	QWC 1
 
(b)	(i)	(use of Dl = (–)l gives)    Dl=656.28 × 10–9  (1)
= 0.88 × 10–9(m) (1)    (0.875 × 10–9(m))
maximum wavelength (= l + Dl) = 657.16 × 10–9 m and
        minimum wavelength (= l – Dl) = 655.41 × 10–9(m) (1)
(ii)	time period = 110 × 60 =6600 s (1)
2pr = vt gives r =  (1)
	 = 4.2 × 108m (1)
(allow C.E. for value of t)	6
[10]
 
8.	(a)	(use of  gives)  (1)
v = (–)2094 km s–1 (1)	2
(b)	graph to show:
correct plotting of points (1) 
straight line through origin (1) 
H =  = gradient = 70 km s–1 Mpc–1 (1)	3
(must show evidence of use of graph in calculation)
[5]

9.	(a)	Δλ/λ = –v/c
	(660.86 – 656.28)/656.28 = (–)v/(3 × 108) (1)
	v = (–) 2094 km s–1 (1)

		2
 
(b)	graph points (1), line through the origin (1)
	H = v/d = slope = 70 (± 4) km s–1 Mpc–1 (1)	3
 
(c)	(i)	supernovae act as standard candles (1)
	known amount of light emitted (absolute magnitude known),
measured amount detected at Earth (apparent magnitude
measured) (1)
	inverse square law can be used to determine distance (1)
(ii)	dark energy (1)	max 3
[8]