SME
Grade 11 Science
Thermal energy, heat and the laws of thermodynamics
The main lesson, then each kind of problem it solves.
Thermal energy, heat and the laws of thermodynamics
Main lesson
Heat to warm something: Q = mcΔT
Use this for “How much heat warms 2 kg of water from 15 °C to 65 °C?”
Melting and boiling: latent heat
Use this for “How much heat turns 0.5 kg of ice at 0 °C into steam at 100 °C, and how long does each stage take with a 500 W heater?”
The first law of thermodynamics
Use this for “A gas takes in 500 J of heat and does 200 J of work pushing a piston out. How much does its internal energy change?”
A heat engine and the Carnot limit
Use this for “An engine takes in 2000 J from a 600 K source and does 500 J of work. How much heat goes to the 300 K sink, and how efficient is it compared with the most it could be?”
A refrigerator
Use this for “A fridge removes 900 J from its 270 K inside using 300 J of work. How much heat reaches the 300 K kitchen, and what are its COP and the best possible COP?”
Which law of thermodynamics?
Use this for “Which law of thermodynamics explains this?”