F4 Physics GS Test Flashcards
Formula for pressure in solids
P = F/A
(Pressure = Force/Area)
Formula for pressure in liquids
P = hgρ
(Pressure = Height x Gravity x Density)
Formula for pressure in gases
P ∝ 1/V
(Pressure is directly proportional to 1/Volume)
What is the unit for pressure?
Pa OR N/m²
(Pascal OR Newton/squared meter)
Why do solids and liquids expand when heated?
Because of the hotter environment, particles speed up and will vibrate more. Their vibrations take up more space, so the solid/liquid expands slightly in all directions.
What is thermal expansion?
The effect that happens to liquids and solids where they expand due to the hot environment around them.
Why would it not be a good idea to reinforce concrete with aluminium rods?
Because aluminium expands more than concrete, so the aluminium rods would crack the concrete.
Why does water expand when it freezes?
The particles in the water (liquid particles) need to re-arrange to become particles in the ice (solid particles). This causes the water to expand a little.
What is contraction?
The opposite of expansion - Solids and liquids will contract slightly due to the cold environment (because of the cold, the particles move more slowly and therefore occupy less space)
What is temperature?
The average kinetic energy between molecules.
How do you calibrate a thermometer?
By finding and marking the ice point and the boiling point.
Name the properties of a thermometer
Range
Sensitivity
Linearity
Responsiveness
Name 4 ways that heat can be transferred by
Conduction
Convection
Radiation
Evaporation
Why are metals good conductors of heat?
Because they have atoms with lots of free electrons
Because the heat energy is passed on by neighbouring particles vibrating along the metal
Why are non-metals poor conductors of heat?
Because they do not have free electrons
Conductor or Insulator:
Metals: ______
Non-metals: ______
Liquids: ______
Gases: ______
Vacuum: ______
Metals: CONDUCTOR
Non-metals: INSULATOR
Liquids: INSULATOR
Gases: INSULATOR
Vacuum: CONDUCTOR
Convection happens mainly in ______.
Fluids (liquids and gases)
What is convection?
The transfer of heat caused by hotter material to rise and colder material to sink under the influence of gravity.
Give one example of convection
Boiling water
What is conduction?
The process by which heat energy is transmitted through collisions between neighboring atoms or molecules in solids.
Give one example of conduction
Using a metal ladle on a hot pan (the heat will transfer from inside the pan to the handle of the ladle)
What is radiation?
Heat traveling through infrared rays (like light waves, but with a longer wavelength)
Give one example of radiation
Standing near a fireplace/campfire and feeling its heat when nearby it
Dark colours are good ______ and good ______.
emitters, absorbers
Bright or shiny colours are ______ emitters and absorbers.
poor
