2023 AQA A-level PHYSICS 7408/1 Paper 1 Question Paper & Mark scheme (Merged) June 2023 [VERIFIED]

2023 AQA A-level PHYSICS 7408/1 Paper 1 Question Paper & Mark scheme (Merged) June 2023 [VERIFIED] internal energy (thermal energy) - -energy of the atoms and molecules of an object due to their movement and position (sum of random distribution of KE and PE of molecules) internal energy can change as a result of (2 things) - -- energy transfer through heating (due to temperature difference) - work done on object (including by electricity) 1st law of thermodynamics - -change of internal energy = total energy transfer due to work done and heating molecules in a solid - -electrical forces hold atoms together, vibrate randomly about fixed positions energy supplied to raise temperature of solid - -increases KE of molecules energy supplied to melt solid - -raises PE of molecules since break free molecules in a liquid - -molecules in contact, move randomly, forces too weak for fixed positions energy supplied to raise temperature of liquid - -increases average KE of molecules energy supplied to vaporise liquid - -enough KE to break free by doing work, raising PE molecules in a gas - -molecules move randomly, far apart energy supplied to raise temperature of gas - -increases KE thermal equilibrium - -when two objects are the same temperature, so no overall heat transfer takes place Celsius scale - -measured in °C, defined in terms of freezing (0) and boiling (100) point of water absolute scale - -measured in °K, starting at absolute zero temperature in °K = - -temperature in °C + 273.15 minimum internal energy when - -object is at absolute zero specific heat capacity - -energy needed to raise 1kg of a material by 1°K