2022 paper corrections

Question 1

why can’t wind power not always meet demands

Answer 1

there is sometimes not enough wind
there are not enough wind turbines
they don’t turn if the wind is too weak/strong

Question 2

how does oiling affect efficiency

Answer 2

efficiency increases
as friction is reduced
so less energy is wasted

Question 3

how does a cloth become positively charged when it rubs a cloth and the rod becomes negatively charged

Answer 3

electrons are transferred from the cloth to the rod
electrons are negatively charged
so there are more positive charges than negative charges on the cloth

Question 4

how does the mass increase when two charged rods are held above it and don’t touch

Answer 4

an additional downward force is on the balance which increases the mass reading
because the held rod is negatively charged
and rods with like charges repel

Question 5

why does a spark jump between a negatively charged rod and earthed conductor

Answer 5

the large potential difference between the two objects
causes negative electrons to move
from the rod to the conductor

Question 6

how is internal contamination from alpha different to external irradiation of alpha

Answer 6

alpha has a low penetrating ability
so alpha radiation is stopped by skin so is low risk
internally alpha radiation is absorbed by living tissue
so alpha radiation is highly ionising
internal contamination will cause harm to dna and can cause cancer

Question 7

how does heat escaping during an experiment measuring vaporisation affect the latent heat value

Answer 7

value is too high
because less energy is transferred to the water

Question 8

how does water evaporating before boiling point affect value for latent heat of vaporisation of water

Answer 8

the measured change in mass is too high
so the value of latent heat is too low