paper 2 / section b
DESCRIPTION
Paper 2 / section b. Suggested answer. Section B Problem Solving Qualitative (Question 9). Question 9. 9 (c). Section C ( Decision Making Skill) ( Section C: Question 11 ). Question 11. 11 (c). Section C ( Decision Making Skill) ( Section C: Question 12 ). 12 (c). Question 12 (d). - PowerPoint PPT PresentationTRANSCRIPT
Paper 2 / section b
Suggested answer
9 (a) (i) 1 Pressure is defined as force per unit area
P=F/A, where F= force, A=area
(ii) 1
1
1
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) 1
1
The depth of sinking increases, pressure increases
As the area of contact increases, the pressure exerted decreases
5
Section B Problem Solving Qualitative (Question 9)
9 (b)
1
1
1
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
Question 9
Suggestion Rationale
1Type 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
9Material for fluid transmission pipe
Plastic/ Aluminium / Steel
10 Strong/ Does not break easily/Does not rust easily/ Non corrosive/withstand temperature/prevent leakage
TOTAL 10
9 (c)
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) 1
1
1
1
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
Section C (Decision Making Skill) ( Section C: Question 11 )
11(b
)1
1
1
1
Heat released by M = Heat absorbed by water
Substitution:(0.5) (800)(100-T)= (0.2)(4200)(T-30)
T= 52.58 oC
Note: no e.c.f
4
(ii) 1 No heat is lost to the surrounding
Question 11
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
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) 1
1
1
When I increases, V increases
The resistance increases
Because temperature increases
(iii) 1 Decrease
Section C (Decision Making Skill) ( Section C: Question 12 )
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 resistanceThickness 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
11(d
)(i)
1
1
Correct substitution
I= P/V
= 11/240
=0.046 A/ 0.05 A
(ii) 1 Heat loss= 11J -10 J=1J
(III)
1
1
Efficiency = Power output x 100%
Power input
= 10 x 100%
11
= 90.91%
5
Question 12 (d)