2020 Paper 2

Question 1

Describe life cycle of stars much more massive than the sun and the formation of new elements

Answer 1

Fusion produces new elements
Stars initially form from a cloud of gas and dust called a nebula. He force of gravity pulls dust and gas togethercausing increasing temperature wich starts the fusion process so the star becomes a protostar. Hydrogen nuclei fuse to form helium nuclei and the star becomes a main sequence star, once hydrogen begins to run out helium nuclei fuse to make heavier elements up to iron. The star then expands to become a red super giant. It then collapses rapidly and explodes to create a supernova, creating elements heavier than iron and distributing them through the universe leaving behind a neutron star of black hole

Question 2

Describe how to reduce effect of random error in experiment

Answer 2

Repeat investigation and ignore anomalies and calculate a mean

Question 3

Describe a method a student could use to get angle of incidence and refraction of

Answer 3

Place a glass box on a peice of a paper. Draw around box. Use ray box to shine light entering the glass block and emerging from the glass box. Join points up to show path of complete ray. Draw normal line at 90 degrees to surface of box. Use protractor to measure angle of incidence and and angle of refraction. Use the ray box to shine a ray of light at a range of different angles of incidence. Increase it in intervals of 10 degrees up until 70

Question 4

Explain why an alternative current is induced in coil when handle of an alternator is turned

Answer 4

As handle moves, coil moves through the magnetic field so cuts magnetic field lines. This induces a potential difference and as the circuit is complete current is also induced. Every half turn the potential difference reverses direction wich also changes direction of current wich produces an alternating current

Question 5

Give a purpose of slip rings

Answer 5

To provide continuous connection between coil and transformer

Question 6

Explain why handle of alternator becomes heavier to turn after it’s disconnected

Answer 6

After disconnection there is no induced current so no magnetic field produced to oppose movement of coil

Question 7

Explain why the door unlocks when the switch is closed

Answer 7

A current can flow around solenoid creating a magnetic field wich attracts the bolt

Question 8

Describe what happens in the electrical circuit when the car aerial absorbs radio
waves.

Answer 8

Electrons oscillate in cuiruit. Current is induced with the same frequency as the radio waves

Question 9

What type of waves are radio waves

Answer 9

Transverse

Question 10

Explain why a car has a maximum speed

Answer 10

Because there is maximum forward driving force provided by the the motor. As speed of the car increases, air resistance increases till air resistance is equa to forward force of car (so resultant force is 0) the car can no longer accelerate as has reached terminal velocity

Question 11

Suggest why you can have a portable power supply that has a generator connected to a transformer that can be adjusted to have different number of turns on the secondary coil

Answer 11

So you can vary the potential difference depending of the device so you don’t need different generators for each type of device