june 2020

Question 1

Describe how the investigation could be improved to reduce the effect of random errors (pulley ting innit)

Answer 1

Repeat measurements
ignore anomalies and calculate a mean

Question 2

The car aerial is connected to an electrical circuit in the car
Describe what happens i. the electrical circuit when the car aerial absorbs radio waves

Answer 2

Alternating current induced in the electrical current
At the same frequency as the radio wave

Question 3

Give two ways in which radio waves are different to sound waves

Answer 3

• Radiowaves are transverse whereas sound waves are longitudinal
• Radiowaves travel at a larger speed
• Radiowaves are electromagnetic
• Radiowaves don’t need a medium

Question 4

Explain why a car has a maximum speed

Answer 4

There is a maximum forward force
As the speed of the car increases air resistance increases
until air resistance and the forward force are equal in size and the resultant force is 0
the car travels at terminal velocity

Question 5

Explain why an alternating current is induced in the coil

Answer 5

The coil cuts magnetic field lines
A potential difference is induced across the coil
Complete circuit so current is induced
Every half turn the potential difference reverses direction
so every half turn the current reverse direction

Question 6

Explain why the handle of the alternator becomes much easier to turn

Answer 6

There is no more induced current
So no magnetic field produced on the coil
Which opposes the motion of the coil