1. Paper 2 / section b
Suggested answer

2. Section B Problem Solving Qualitative (Question 9)1
Pressure is defined as force per unit area
P=F/A, where F= force, A=area
(ii)
Depth of singking in Diagram 9.1 is deeper than in Diagram 9.2
The weight/load of the man in Diagram 9.2 and Diagram 9.1 is equal
Area of contact with the sand in Diagram 9.2 is larger than in Diagram 9.1
(iii)
The depth of sinking increases, pressure increases
As the area of contact increases, the pressure exerted decreases 5

3. The fan blows /remove/push/force air out the vents
Question 9 9
(b) 1
The fan blows /remove/push/force air out the vents
Produce a partial vacuum area in the vacuum cleaner/low pressure
Atmospheric pressure is higher than the pressure inside the vacuum cleaner/Difference in pressure
Push the dirt into the vacuum 4

4. 9 (c) Suggestion Rationale 1 Type of fluid Oil 2
Incompressible/ No air bubble/Cannot be compress/water produce air bubble
Any 5 correct 3
Characteristic of fluid
High boiling point/ Low density/ High viscosity 4
Does not change to gases state easily/lighter/Less friction/Does not evaporate easily 5
Size of the master piston
Small 6
To produce high pressure/small force used 7
Size of slave piston
Big 8
To produce a big force on the disc/ Force is directly proportional to area 9
Material for fluid transmission pipe
Plastic/ Aluminium / Steel 10
Strong/ Does not break easily/Does not rust easily/ Non corrosive/withstand temperature/prevent leakage
TOTAL

5. Two bodies are said to be in thermal equilibrium when
Section C (Decision Making Skill) ( Section C: Question 11 ) 11
(a)
(i) 1
Two bodies are said to be in thermal equilibrium when
Both bodies are at the same temperature/ The net heat flow between the two bodies is zero/ There is no net heat flow between them
(ii)
Heat flows from hot water to thermometer
Achieve thermal equilibrium
Temperature of water is the same as temperature shown by thermometer
No more heat flows at 100 oC 4

6. Heat released by M = Heat absorbed by water
Question 11 11
(b) 1
Heat released by M = Heat absorbed by water
Substitution:
(0.5) (800)(100-T)= (0.2)(4200)(T-30)
T= oC
Note: no e.c.f 4
(ii)
No heat is lost to the surrounding

7. 11 (c)
Characteristics
Explanation
Hollow plastic stopper
Bad conductor of heat /Reduce heat loss/bad conductor/good insulator/reduce heat escape to the surrounding/Trapped air
Space X is vacuum
Prevent heat lost from the sides through convection/heat cannot travel through vaccum
Double walled tube made of glass
High specific heat capacity/
Becomes hot very slowly
Double walled tube coated by shiny paint
Reflect heat from the wall of thermos flask/not absorb heat
The most suitable is W
Because
Hollow plastic stopper, space X is vacuum, double walled tube made of glass and coated by shiny paint

8. Work done in moving one coulomb of charge from one point to another /
Section C (Decision Making Skill) ( Section C: Question 12 ) 12
(a)
(i) 1
Work done in moving one coulomb of charge from one point to another /
Energy dissipated per unit charge by the resistor /
V= E/Q, E= work done, Q= quantity of charge
(b)
(ii)
When I increases, V increases
The resistance increases
Because temperature increases
(iii)
Decrease

9. 12 (c)
Characteristics
Explanation
Shape of filament wire
Coiled
So that a very long wire can be fitted inside the glass bulb to give out a bright light /
High resistance
Thickness of the filament wire
Thin
To give more resistance per unit length/
More heat
Type of wire
Tungsten
Has high melting point/
Does not break easily
Pressure in the bulb
Low pressure
The bulb will not burst/explode after for a long time
The most suitable is R
Because
Coiled , thin wire, nitrogen at low pressure

10. Efficiency = Power output x 100% Power input = 10 x 100%
Question 12 (d) 11
(d)
(i) 1
Correct substitution
I= P/V
= 11/240
=0.046 A/ 0.05 A
(ii)
Heat loss= 11J -10 J=1J
(III)
Efficiency = Power output x 100%
Power input
= 10 x 100%
= 90.91% 5