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P4.3 - Thermal
Thermal Physics - OCR A2 Physics
Question | Answer |
---|---|
Define heat: | A measure of the total thermal energy in a system. |
Define temperature: | A measure of the average kinetic energy of particles. |
Define specific heat capacity: | The energy required to raise the temperature of 1kg of substance by 1 degree. |
Define specific heat of vaporisation: | The energy required to change 1kg of liquid into 1kg of gas at constant temperature. |
Define internal energy: | The sum of all the kinetic and potential energies of molecules within a substance. |
What is the pressure law? | At constant volume, pressure is directly proportional to the temperature. |
What is Boyle's law? | At a constant temperature, pressure and volume are inversely proportional. |
What is Charles' law? | At a constant pressure, the volume is directly proportional to the temperature. |
Define pressure: | Force per unit area, it is the result of collisions between particles themselves, or particles and the walls of their container. |
Give three assumptions used in the kinetic theory of gases: | The gas consists of a large number of molecules. The molecules move randomly. Collisions are elastic. |
What is the equation for the kinetic energy in a single atom? | KE = 3/2KbT |
What is the equation for the kinetic energy in a mole? | KE = 3/2nRT |
What is an absolute scale of temperature? | A temperature scale measured from absolute zero in kelvins. |
What changes and what remains constant during a change in state of a system? | The internal energy changes, the temperature doesn't. |
What is Brownian motion? | The observation of random motion in air/smoke particles. The experiment saw the smoke particles appear as bright specks moving in a completely random motion. |
What happens to a gas as the temperature increases? | The average speed increases, the maximum speed increases, and there is a wider range of speeds. |
What is an ideal gas? | A gas that has internal energy only in the form of random kinetic energy. |