PHYSICS P1 2021

The idea of obtaining power from nuclear fusion was investigated using models.

The models were tested before starting to build the first commercial nuclear fusion power station.

Suggest two reasons why models were tested (2)

any two from:

• to make sure the fusion process is possible

• to develop an understanding of the process

• to assess the efficiency of the process

• to make predictions

• assess safety risks

• assess environmental impact

• set-up cost is lower (for small scale experiments)

It is unlikely that all of the electricity that the UK needs can be generated by solar power systems.

Explain why (2)

Alpha decay nuclear equation

Beta decay nuclear equation

• current would be (almost) zero

• because the switch has zero resistance or the p.d across the variable resistor is zero

• more than 0.20J

• (because) the car needs to be moving at the top of the loop

or

because the car needs to be moving to complete the loop

or

not all Ek at B will transferred to gpe at C

When the volume of gas in the syringe increased, the pressure on the inside walls of the syringe decreased. Explain why (3)

• less frequent successful collisions between particles and walls of the syringe

• so there is a lower force on the walls of the syringe

• and pressure is the total force per unit area

Explain the advantage of transmitting electricity at a very high potential difference (3)

• very high p.d means very low current

• which means less thermal energy transferred to surroundings or less power loss in cables

• which increases efficiency of power transmission

• electric field strength is very high

• causing the air to become ionised

• (the kite/string) conducts charge to the person/earth

• the p.d. across the wires/cable is the same

• but the resistance of the steel wire is greater (so there is less current in the steel)