(i) any two eg proton, neutron 2
(ii) 1
(b) (i) contains a strange quark 1
or longer half life than expected
or decays by weak interaction
(ii) the
... [Show More] second one because lepton number is not conserved 2
lepton number LHS = 0 RHS -1 + -1 = -2
(c) (i) weak (interaction) 1
(ii) X must be a baryon 2
baryon number on right hand side is +1
[Total 9 marks]
2 (a) (i) (moment = 520 x 0.26) = 140 (135.2)
Nm 2
(ii) 180 x 0.41 and 0.63 X seen 3
135.2 = 180 x 0.41 + 0.63 X
ecf from (a)(i)
(X = (135.2 – 73.8) / 0.63)
= 97 (N) (97.46)
allow 105 from use of 140Nm ecf from (a)(i)
(iii) (520 – (180 + 97.46)) 1
= 240 (242.5 N)
ecf (or from correct moments calculation)
[Total 6 marks]
A-LEVEL PHYSICS MARK SCHEME
Practice Paper 1 Maximum marks: 85
View detailed guidance on the conclusions you can draw from your students' performance in
these papers on the MERiT welcome page. Understand how your students compare with
others and target revision effectively by entering marks into MERiT.
This document is licensed to Haggerston School - MB260045
Page 2
3 (a) (momentum of air) increases ✔ 1
words implying increase
(b) (rate of change of momentum so) force acting on the air (Newton 2) ✔ 3
it/air exerts force (on engine) of the same/equal magnitude/size ✔
but opposite in direction (Newton 3) ✔
allow backwards and forwards to indicate opposite
(c) (use of F = ∆mv/t) 1
F = 210 × 570 = 120 000 (N) (119 700) ✔
(d) Momentum/velocity is a vector ✔ 2
Momentum/velocity has a direction ✔
There is a change of direction ✔
A direction change is a momentum change ✔
Any of above points - max 2 marks.
(e) use of v2
= u2
+2as 2
forgetting to square u or double a score 1 mark
0 = 682
− 2 × 2.7 × s ✔
s = 682
/(2 × 2.7) = 860 (m) (856) ✔
accept range 850 − 860
accept alternative method
first mark for time calculation AND correct substitution
second mark using s = ut +1/2at2 OR average speed
(f) rate of intake of air decreases (as plane slows) OR volume/mass/amount 2
of air (passing through engine) per second decreases ✔
allow argument in terms of (air) resistance for 1 mark only
i.e air resistance decreases as speed of aircraft decreases
(as) smaller rate of change of momentum OR momentum change ✔
NOT FRICTION
[Total 11 marks]
Q4 (a) (current in) steel wire (is less than the current in an) aluminium wire as it 3
has a higher resistivity / resistance OR aluminium is better conductor✓
the six aluminium wires are in parallel OR total cross-sectional area of aluminium
is 6 times greater than steel wire✓
each aluminium wire carries three times as much current as the (single) steel wire✓
(b) If the steel wire is ignored then can score first and third marks 3
For correct answer accept range 32 kW to 33 kW [Show Less]