Physics P2 Unofficial Markscheme Edexcel.Watch
Special thanks to everyone in this thread, especially grace143. Reps have been given to contributors, however, it has been restricted to 1rep/day.
a. What is the diagram pointing to? (1)
Answer - Proton.
b. Why does the girl get positively charged as she walks across the nylon carpet? (3)
Answer - The insulating soles of the girl’s shoes rub against the nylon carpet (1)
Electrons are transferred (1)
From the girl to the carpet (1)
c. Why does she get a small electric shock when she touches the metal handle of the door? (2)
Answer - Metal is a conductor (1)
Charge flows from the metal to the girl, as the girl is positively charged (1)
For an easy route to the ground (1)
Earthing mentioned (1)
d. Math question.
Answer - 6.3C (0.07A * 90)
Q2. Nuclear Fission & Fusion.
a. What is the difference between a fission and fusion reaction?
b. Fill in the blanks (number of protons and neutrons)
Protons - 92
Neutrons - 143
d. Graph question about correlating temperature and fusion reactions per second.
Answer- Fusion needs a high temperature to overcome repulsion between positive nuclei. The graph shows a correlation between the increase in rate of fusion reaction per second and temperature - as temperature increases, so does rate of reaction. (thank you to L0st45!)
Alternative Answer- Fusion works best at high temperatures because this is needed to overcome the electrostaticrepulsion of the (positive) nuclei. As the temperature increases, the nuclei move around fasterbecause they have more energy. This increases the number of collisions of nuclei, therefore increasing the rate of the nuclear reaction. This means there are more fusion reactions per second. (thank you to grace143!)
e. Some scientists claimed that they could perform fusion reactions under room temperatures. Explain why this claim is no longer believed.
Answer- This claim was never validated, i.e, verified by other scientists and carried out.
Q3. Half Life (I think)
a. Half life of Iodine-131.
Answer- 8 days.
b. Estimate half life of Iodine-131 8 days ago.
c. Why do hospital staff have increased risks from handling Iodine-131?
Answer- Beta and gamma are ionising radiation (1)
If they enter the body, they could collide with (molecules of) genetic material / DNA (1)
This could cause cell mutations (1)
Which may lead to tissue damage / cancer (1)
d. Name some precautions taken to prevent being affected by Iodine-131.
Answer- Tongs/Special Suits.
e. What emitter is used for paper rollers?
Answer - Beta emitter.
f. How does this system work?
The beta roller passes through the paper and the detector keeps a track on how many beta particles pass through. If the paper is too thick, beta count drops and the detector sends a signal to reduce pressure on the paper. If the paper is too thin, beta count is too high and the detector sends a signal to increase pressure on the paper.
Q4. Rollercoaster Question
a. 2.37 million/1.71 million
b. 1.71 million.
c. Energy transfer when the rollercoaster moves from C to D.
GPE to Kinetic Energy, as it loses its GPE as it moves downward and according to conservation of energy, it changes to kinetic energy.
Q5. Volts Question
a. Draw the voltmeter.
b. 12 Volts can be written as :
Answer - 12 Joules per coulomb.
c. Prove that the resistance is 11 ohms.
Answer- The resistance was 10.8 ohms, which is about 11 ohms
e. Six marker on filament lamp.
a. Acceleration of the graph.
Answer : y/x to get gradient = 6 m/s^2 - 6.25m/s^2
b. Draw the graph for a cyclist with a smaller acceleration.
c. Why does the cyclist need to keep pedaling?
Answer- To overcome air resistance and maintain the same velocity.
e. Six marker on bike/clothes.