Energy Changes in a System (AQA GCSE Physics Combined Science): Quizzes
📚Quizzes
Practise the questions
12 questions from this quiz
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Practise the questions
12 questions from this quiz
What is the formula for calculating efficiency?
What is the formula for calculating efficiency?
What does thermal conductivity measure?
What does thermal conductivity measure?
How well a material lets thermal energy pass through it
Which THREE factors affect the rate of thermal energy transfer through walls?
Which THREE factors affect the rate of thermal energy transfer through walls?
Temperature difference, thickness, conductivity
What do all machines waste some energy as?
What do all machines waste some energy as?
Heat
What is the maximum possible efficiency of any machine?
What is the maximum possible efficiency of any machine?
Less than 100%
A motor uses 100J of energy. 60J becomes useful kinetic energy. What is its efficiency?
A motor uses 100J of energy. 60J becomes useful kinetic energy. What is its efficiency?
60%
Which materials have high thermal conductivity?
Which materials have high thermal conductivity?
Metals like copper and aluminium
Which materials have low thermal conductivity?
Which materials have low thermal conductivity?
Wood, plastic, and air
How does lubrication improve machine efficiency?
How does lubrication improve machine efficiency?
It reduces friction in moving parts
What effect do thicker walls have on thermal energy transfer?
What effect do thicker walls have on thermal energy transfer?
They slow down energy transfer
How does a bigger temperature difference affect thermal energy transfer?
How does a bigger temperature difference affect thermal energy transfer?
It makes energy transfer faster
How do streamlined shapes improve efficiency in moving objects?
How do streamlined shapes improve efficiency in moving objects?
They reduce air resistance