Energy transfers and efficiency (AQA GCSE Physics): Quizzes
📚Quizzes
Practise the questions
12 questions from this quiz
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Practise the questions
12 questions from this quiz
What direction does thermal energy transfer occur?
What direction does thermal energy transfer occur?
From warm places to cooler places
Which three factors affect the rate of thermal energy transfer through a wall?
Which three factors affect the rate of thermal energy transfer through a wall?
Temp. difference, thickness, conductivity
What happens to heat transfer rate when the temperature difference increases?
What happens to heat transfer rate when the temperature difference increases?
Heat transfers faster
How does increasing wall thickness affect thermal energy transfer?
How does increasing wall thickness affect thermal energy transfer?
Slows down heat transfer
What does thermal conductivity measure?
What does thermal conductivity measure?
How well material conducts heat
Which materials have high thermal conductivity?
Which materials have high thermal conductivity?
Metals
Which materials have low thermal conductivity?
Which materials have low thermal conductivity?
Plastic and wood
What does efficiency measure?
What does efficiency measure?
How well devices transfer useful energy
What is the formula for efficiency?
What is the formula for efficiency?
What are the units of efficiency?
What are the units of efficiency?
Efficiency has no units
What is the maximum possible efficiency of any machine?
What is the maximum possible efficiency of any machine?
100%
A motor uses 100J of energy. If 60J is useful kinetic energy, what is its efficiency?
A motor uses 100J of energy. If 60J is useful kinetic energy, what is its efficiency?
60%