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Ques. Comment Recommendation
anyone.
 Wash hands and face after
use of the source.
 Keep the source away
from the body.
(c)(iii) “…. Total mass of elements….”. This will Credit should be given for
mean only the Barium and Krypton since the both … including the
neutron is not an element neutron and not including
the neutron
Either: Mass of [Ba + Kr +
-27
3n] = 390.190 x 10 kg
-25
OR 3.90190 x 10 kg
OR: Mass of [Ba + Kr ] =
-27
385.180 x 10 kg OR
-25
3.85180 x 10 kg
4b(ii) 2013 Syllabus Section A  Students could have used
Specific Objective 4.1 define the terms: average velocity v̅ = 0+18
distance, displacement, speed, velocity, = 9 ms 2
-1
acceleration; Distance and displacement, s or And distance x = v̅ t = 9 x
x; speed and velocity, v; acceleration, = − .
18 = 16.2 m
Specific Objective 4.2 apply displacement- But Average velocity is
time and velocity-time graphs; Finding the NOT MENTIONED on
gradient for straight lines only the syllabus.
Equations of motion are NOT on the syllabus,  If students had been
so student cannot use them to find distance. advised to sketch a
velocity-time graph and
hence find distance, they
would have been able to
find distance from the
area under the graph =
1
area of triangle = X 1.8
2
x 18 = 16.2 m
 What will you give students

who wrote v =

x = v t = 18 x 1.8 = 32.4 m ?
5a  Will students understand that “appropriate (a)(i) Car radiator: [any 2?]
characteristics” means rough or smooth, Nature : Dull – Emits
etc.? radiation (to
 The statement is ambiguous. Since two surroundings)/ Good
cases are given students may give one factor emitter
for each case. Colour : Black – Emits

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