# AQA AS Physics 7407/2 UnOfficial Markscheme 2018

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#1
Paper 2

1.1:
d = 10*10^-2
Passed through First lg IN 0.5s = 10/0.5 = 20cms
Second Lg = 25cms
∆a/1.19
4.2 x 10^-2m (3 Marks)

1.2: Time to travel between first and second gate is much greater in ‘B’ than ‘A’ additionally ‘B’ has a higher average speed (2 Marks)

1.3: G = ∆y/∆x = 0.048 (2 Marks)

1.4:
h = 2G/g
h = 9.8 x 10^-3m (1 Marks)

1.5: To determine constant of proportion for at least 2 points and compare (1 Marks)

2.1: Check for zero error readings and reset it if doesn’t read 0 when completely closed
Exclude anomalous values (2 Marks)

2.2: Draw gap above caliper (1 Marks)

2.3:
D = 59.9 x 10^-3m H = 12.09 x 10^-3m
L = 19..32 x 10^-3m
Volume = Surface area x height
Volume = (𝛑D^2/4 - 𝛑L^2/4) x H
Volume = 3.1 x 10^-5 2sf
(3 Marks)

2.4: Add additional masses until h is reduced to 50% of original value
Add clay to increase this weight
Use a ruler and set square to measure height
Plot graph of F against 1/h^3
Make line of best fit
Set equal to ‘k’ and substitute total weight into formulae ‘k’
(5 Marks)

3.1:
m = eQ/ specific charge = 1.6x10^-19/4.81x10^7 = 3.33 x 10^-27kg
V = rt (2Ek/m) = 2.2 x 10^7 ms^-1
(2 Marks)

3.2:
W = Fs
F = w/s
8.1 x 10^-13J/3.5x10^-2m =2.3x10^-11N
(2 Marks)

3.3:
5.1x10^4 ios/s x 3.5 = 1.785x10^5
1.785/8.1x10^-13 = 28.4 eV
(3 Marks)

3.4:
Q = 0.85x10^-3A x 1.2x10^-9s = 1.02x10^12As
Charge Carriers = As/Q(electron Charge) = 6.4 x 10^6
(2 Marks)

3.5:
When >3.5cm there's no charge in potential difference when the radioactive source is near (5cm) and ionisation occurs, Potential difference across the air gap is 250V
(3 Marks)

4.1:
Speed in A = 2.05e8 Refractive index = 1.4161
c/na = 2.05e8 x (1 - 0.03252) = 1.9885e8
Speed in glass A = 0.9678
na/speed a = 1.4161/0.086748
nB = 1.51
(3 Marks)

4.2:
At constant velocity the strain is the same as no force which would return the value back to 0, this is the same for when the object is at rest. While it’s accelerating strain would decrease
(⅔ Marks)

4.3:
Option Q is the better choice as it’s more efficient requiring and therefor more effective than option P
(½ Marks)

5) A
6) C
7)B
8)C
9)C
10)D
11)D
12)C
13)A?
14)D
15)B
16)B
17)D
18)B
19)A
20)C
21)C
22)D
23)D
24)D
25)A
26)A
27)A
28)A
29)D
30)C
31)D
32)A
33)B
34)B
Last edited by NeonRyse; 2 years ago
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