OCR 21st Century 16th June P4 P5 P6 unofficial mark scheme

For question 1b, I thought they weren't an interaction pair because both air resistance and weight act on the same object (the ball), but forces in an interaction pair have to act on different objects. Is this right?

The grade boundaries for additional Physics exams rarely exceed 40 marks for the A* benchmark. Therefore, I'd say given that it was only slightly easier than last year's paper, we can expect the A* boundary to be 38-42 marks.

EASIER than last year? No way.

I found last year really easy, I don't know. I found that I ran out of time for this one...and the conversions were hell.

I think for the second question you were meant to mention terminal velocity?

Approximately what mark did you get last year, and how does that compare to what mark you think you got today?

there was one about hitting the ball at the same velocity with less force? i put
1) streamlined ball reduces air resistance
2) use a lighter ball

Unofficial mark scheme please help so we can fill out all the answers
These answers have been verified by many but could be wrong

Predicted Boundaries
Full UMS - 43
A* - 37
A - 30
B - 23
C - 18

Forces question(3)
Arrow up for reaction
Arrow going to the left for friction
Arrow going to the right as push

Resultant force(2)
Yes it is 0 as speed is constant, forces equal no acceleration

KE mass of ball(2)
50g

Reasons why ke isnt transferred: (2)
Heat energy lost
Sound energy lost

Momentum(2)
2kg m/s

Circle time(1)
0.5ms

Keeping velocity same and decreasing force(2)
Change in momentum = force x time so increasing the time the force is acting on the ball will make up for the lower force

6 marker
Draw the graph
Talk about velocity and acceleration at different points
Definition of displacement

Current question(2)
150A

Circuit drawing(2)
Voltmeter parallel to the motor
Ammeter anywhere else

Lamp and current question(2)
Current in a parallel circuit is added up so it is 2A + 2A and not 4A when the lamp is broke

Electric cars(2)
Advantage - No air pollution from burning fuel in engines, co2 emissions, global warming
Disadvantage - electricity being made causes pollution at the power station

Terminal and electrons(1)
To the positive terminal

Transformer(3)
Alternating current in primary constantly changes direction of magnetic field in core
Electromagnetic induction provides alternating voltage in secondary
How turns affect the step up or step down conversion

Transformed voltage circle(1)
4v

6 marker
- Calculation of resistances(it was in mega amps)
- Proving it was negatively correlated using figures
- Description of a thermistor
- Proving there was correlation for the second one
- explanation of why current is higher(less resistance = less collisions between ions and electron)

Background radiation(1)
Always present radiation

Affect of distance to meter(1)
Counts increase
Half life no change

Irradiation and Contamination(3)
-Exposure to source only for the time you are near it e,g, in an area of lots of radon gas
-Physical and direct contact with source e.g. touching radioactive granite
-Irradiation is less harmful, contamination more harmful e.g. Damaging internal organs

Dan and Lucy(3)
-100 to 50 shows dan is correct
-Varying rates for the half lives after that show that background radiation is having an impact and lucy is correct
-calculations for the half lives

Half lives(1)
2

Nuclear equation(2)
222 on top and 52 on bottom

Similarity and Difference between 2 radon isotopes(2)
1. Both have same number of proton
2. Have different number of neutrons

6 marker
- 2000msv is very high to ensure killing of living cells in the tumour
- Description of ionisation
- The radiation is directed carefully at the tumour so cancers dont form elsewhere
- irradiation of other patients and doctors avoided through use of concrete blocks during process and keeping the patient separate to others

Unofficial mark scheme please help so we can fill out all the answers
These answers have been verified by many but could be wrong

Predicted Boundaries
Full UMS - 43
A* - 37
A - 30
B - 23
C - 18

Forces question(3)
Arrow up for reaction
Arrow going to the left for friction
Arrow going to the right as push

Resultant force(2)
Yes it is 0 as speed is constant, forces equal no acceleration

KE mass of ball(2)
50g

Reasons why ke isnt transferred: (2)
Heat energy lost
Sound energy lost

Momentum(2)
2kg m/s

Circle time(1)
0.5ms

Keeping velocity same and decreasing force(2)
Change in momentum = force x time so increasing the time the force is acting on the ball will make up for the lower force

6 marker
Draw the graph
Talk about velocity and acceleration at different points
Definition of displacement

Current question(2)
150A

Circuit drawing(2)
Voltmeter parallel to the motor
Ammeter anywhere else

Lamp and current question(2)
Current in a parallel circuit is added up so it is 2A + 2A and not 4A when the lamp is broke

Electric cars(2)
Advantage - No air pollution from burning fuel in engines, co2 emissions, global warming
Disadvantage - electricity being made causes pollution at the power station

Terminal and electrons(1)
To the positive terminal

Transformer(3)
Alternating current in primary constantly changes direction of magnetic field in core
Electromagnetic induction provides alternating voltage in secondary
How turns affect the step up or step down conversion

Transformed voltage circle(1)
4v

6 marker
- Calculation of resistances(it was in mega amps)
- Proving it was negatively correlated using figures
- Description of a thermistor
- Proving there was correlation for the second one
- explanation of why current is higher(less resistance = less collisions between ions and electron)

Background radiation(1)
Always present radiation

Affect of distance to meter(1)
Counts increase
Half life no change

Irradiation and Contamination(3)
-Exposure to source only for the time you are near it e,g, in an area of lots of radon gas
-Physical and direct contact with source e.g. touching radioactive granite
-Irradiation is less harmful, contamination more harmful e.g. Damaging internal organs

Dan and Lucy(3)
-100 to 50 shows dan is correct
-Varying rates for the half lives after that show that background radiation is having an impact and lucy is correct
-calculations for the half lives

Half lives(1)
2

Nuclear equation(2)
222 on top and 52 on bottom

Similarity and Difference between 2 radon isotopes(2)
1. Both have same number of proton
2. Have different number of neutrons

6 marker
- 2000msv is very high to ensure killing of living cells in the tumour
- Description of ionisation
- The radiation is directed carefully at the tumour so cancers dont form elsewhere
- irradiation of other patients and doctors avoided through use of concrete blocks during process and keeping the patient separate to others

Unofficial mark scheme please help so we can fill out all the answers
These answers have been verified by many but could be wrong

Predicted Boundaries
Full UMS - 43
A* - 37
A - 30
B - 23
C - 18

Forces question(3)
Arrow up for reaction
Arrow going to the left for friction
Arrow going to the right as push

Resultant force(2)
Yes it is 0 as speed is constant, forces equal no acceleration

KE mass of ball(2)
50g

Reasons why ke isnt transferred: (2)
Heat energy lost
Sound energy lost

Momentum(2)
2kg m/s

Circle time(1)
0.5ms

Keeping velocity same and decreasing force(2)
Change in momentum = force x time so increasing the time the force is acting on the ball will make up for the lower force

6 marker
Draw the graph
Talk about velocity and acceleration at different points
Definition of displacement

Current question(2)
150A

Circuit drawing(2)
Voltmeter parallel to the motor
Ammeter anywhere else

Lamp and current question(2)
Current in a parallel circuit is added up so it is 2A + 2A and not 4A when the lamp is broke

Electric cars(2)
Advantage - No air pollution from burning fuel in engines, co2 emissions, global warming
Disadvantage - electricity being made causes pollution at the power station

Terminal and electrons(1)
To the positive terminal

Transformer(3)
Alternating current in primary constantly changes direction of magnetic field in core
Electromagnetic induction provides alternating voltage in secondary
How turns affect the step up or step down conversion

Transformed voltage circle(1)
4v

6 marker
- Calculation of resistances(it was in mega amps)
- Proving it was negatively correlated using figures
- Description of a thermistor
- Proving there was correlation for the second one
- explanation of why current is higher(less resistance = less collisions between ions and electron)

Background radiation(1)
Always present radiation

Affect of distance to meter(1)
Counts increase
Half life no change

Irradiation and Contamination(3)
-Exposure to source only for the time you are near it e,g, in an area of lots of radon gas
-Physical and direct contact with source e.g. touching radioactive granite
-Irradiation is less harmful, contamination more harmful e.g. Damaging internal organs

Dan and Lucy(3)
-100 to 50 shows dan is correct
-Varying rates for the half lives after that show that background radiation is having an impact and lucy is correct
-calculations for the half lives

Half lives(1)
2

Nuclear equation(2)
222 on top and 52 on bottom

Similarity and Difference between 2 radon isotopes(2)
1. Both have same number of proton
2. Have different number of neutrons

6 marker
- 2000msv is very high to ensure killing of living cells in the tumour
- Description of ionisation
- The radiation is directed carefully at the tumour so cancers dont form elsewhere
- irradiation of other patients and doctors avoided through use of concrete blocks during process and keeping the patient separate to others

For question 1b, I thought they weren't an interaction pair because both air resistance and weight act on the same object (the ball), but forces in an interaction pair have to act on different objects. Is this right?

Exactly what I got. I said that in an interaction pair, the opposite forces act on opposite bodies. However, I think that is only 1 mark and for the other you had to talk about how he was also correct because the resultant force was 0 or something like that.

I also wrote the resultant force part, but now I'm thinking whether they are actually an interaction pair. Does weight act on the ball or the air?

They were not an interaction pair. In an interaction pair, the forces act on opposite bodies, whilst in this example, both forces only acted on the ball. Also, weight (gravity) and air resistance are different types of forces.