Question Constellation Sign up for free AQA · GCSE · Physics · Higher
Air-Particle Motion and Turbine Power
The generator works when forces from the compressed air cause a turbine to rotate. When particles of air collide with the turbine they transfer energy to the turbine. In warm weather the temperature of the compressed air increases, increasing the pressure inside the storage tank.
Explain how the motion of the particles in warmer air causes an increase in the power transferred to the turbine.
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Marking points
- 1 States that warmer air particles have greater average speed or kinetic energy.
- 2 States that collisions with the turbine become more frequent.
- 3 States that each collision exerts a greater force.
- 4 Links the collision changes to more energy transferred each second.
Full-mark answer
At the higher temperature, the air particles have a greater average speed. They collide with the turbine more frequently, and each collision exerts a greater force. As a result, more energy is transferred to the turbine each second, so the power transferred increases.
Why this answer loses marks
The gas particles vibrate more.
Gas particles move faster rather than vibrating about fixed positions; connect this to changed collisions and transfer rate.