Paper 1 practice questions

Question 1

The power output of the lamp is 1W when the pd is 5V
a student predicts the poweroutput will be 4W if the potential difference was increased

Answer 1

The current and the pd would both need to increase but the current will not double because the resistance of the filament lamp increases.

Question 2

a student became negatively charged because of the friction between his socks and the carpet
explain why the friction causes the student to become charged

Answer 2

the transfer of electrons from the carpet to the student

Question 3

a negatively charged student touches a metal tap and receives an electric shock explain why

Answer 3

Because of the potential difference between the student and the tap
causes a transfer of electrons which charges.

Question 4

Some carpets have thin copper wires running through them
the student is less likely to receive an electric shock after walking on this type of carpet.

Answer 4

The carpets have lower resistance so no build up of charge

Question 5

How does a cyclist going uphill affect their maxmium speed?

Answer 5

Maximum speed will be lower
because maximum power output is constant
so their is additional work done against gravity

Question 6

explain how the resistance of a filament lamp changes as the potential difference across it increases

Answer 6

Potential difference increases
so current increases
filament lamp temperature will increase so resistance increases

Question 7

The internal energy of the air increases as a tyre is inflated
explain why w

Answer 7

work done on the tyres

so temperature increases

Question 8

The power output of the turbine is directly proportional to the kinetic energy of the air passing the blades each second
describe the effect on the power output when the wind speed is halved.

Answer 8

When the wind speed is halved the kinetic energy is decreased by half

wind speed is halved decreasing the kinetic energy by 4

so kinetic energy decreases by a factor of 8