Youth New World Mock Exam For U 2016
Physics Paper 2 Marking Scheme
Section A:
1.
2.
3.
4.
5.
6.
7.
8.
D
D
B
C
A
B
C
A
(a) (i)
Point A
v 0  
(ii)

c
0
2000 103 656.3  

3 108
656.3
  651.9 nm
2 
(b) v  r 

 T 
(c)
1M for formula
1A
1M
2


2000 103  r 

15

365

24

60

60


1M for 2000 km s-1
r  1.511014 m
1A
GMm mv 2

r2
r
1M for formula
2
6.67 1011 M
  2000 103 
14
1.5110
M  9.03 1036 kg
(d)
1A
tan 0.12'' 
r
distance
1A
1M
1.511014
tan 0.12'' 
distance
distance  2.59 1020 m
= 27400 ly
1A
Section B
1.
2.
3.
4.
5.
6.
7.
8.
C
B
C
C
C
A
B
A
(a)
(i)
According to classical theory of electromagnetism, accelerating electron
radiates,losing its energy, and will finally collapse into the nucleus.
(ii) The Bohr model assumes that the orbiting electron don’t radiate/ stay in a
stable orbit.
(b)
(i) Min:
E = 0 – (-13.6eV) = hc/𝜆
𝜆 = 912𝑛𝑚
Max:
E = (-13.6eV/4) – (-13.6eV)= hc/𝜆
𝜆 = 121𝑛𝑚
(c) (Sorry, I better say that this question should be cancelled as the question is a bit
different from what I wrote before.)
Unlike dilute hydrogen atom, the energy level of hydrogen in Sun should be
densely distributed so that the energy difference between each successive energy
level is small, hence producing a continuous spectrum.
Any diagram showing correct method to form spectrum from Sun is acceptable.
Section C
1.
2.
3.
4.
5.
6.
7.
8.
C
C
A
B
A
B
D
D
Section D
1.
2.
3.
4.
5.
6.
7.
8.
C
B
A
A
D
B
B
B
Solution
(a) (i)
Converge to the retina
Virtual image on unaided near point
(ii) Convex lens
Plens = +2.41 D
1A
1A
1A
1A
(b)
(i) Reflection of ultrasound at different boundary/when entering another tissue.
1A
The amplitude in a A-scan image is proportional to the intensity of the reflected
ultrasound signal/change in acoustic impedance.
1A
Distance/depth calculated from time for signal to return to ultrasound transducer.
1A
(ii)
Time different between Post lens and Ant lens =
8 - 3 s = 5 x 10-6 s
1M
-6
Distance = 1640 (5 x 10 )/2
= 4.1 x10-3m
1A
(iii) a layer of gel (i.e. coupling medium) with acoustic impedance close to soft tissue
is applied to patient’s skin/ It can avoid most ultrasound waves from being reflected
by any possible air layer.
1A