Physics 1A Flashcards
Name the 3 ways heat is transferred
Radiation
Conduction
Convection
What is heat radiation transferred by ?
Infrared radation
What is conduction and convection transferred by ?
Particles
What is the main form of heat transfer in solids ?
Conduction
What is the main form of heat transfer in liquids and gases ?
Convection
What is infrared radiation emitted by ?
Solids, liquids and gases
What objects can both emit and absorb infrared radiation?
Any
Why can you feel infrared radiation if you stand near something hot ?
An object that’s hotter than it surroundings emits more radiation than it absorbs
Why do dark, matt surfaces absorb infrared radiation better than light, shiny surfaces ?
Lights, shiny surfaces reflect more infrared radiation than it absorbs.
What is Specific Heat Capacity (SHC)
The amount of energy needed to raise the temperature of 1kg of a substance by 1 degrees.
What is the equation to work out Specific Heat Capacity?
Energy transferred= mass x SHC x temperature change
(J) (kg) (J/kg) (C)
What is the Kinetic Theory?
It describes how particles move in solids, liquids and gases.
What is kinetic energy?
The energy an object/particle has because of its movement.
How does Kinetic Theory explain the arrangement of particles within a solid?
- Strong forces of attraction hold the particles close together in a fixed, regular arrangement
- The particles don’t have much energy so they can only vibrate about their fixed positions.
How does Kinetic Theory explain the arrangement of particles within a liquid?
- There are weaker forces of attraction between the particles.
- The particles are close together but can move past each other- forming irregular arrangement
- They move in random directions at a slow speed
How does Kinetic Theory explain the arrangement of particle within a gas?
- There are almost no forces of attraction between particles
- They are free to move and travel in random directions at high speeds
What happens to a substance if you heat it?
You give the particles more kinetic energy so they vibrate and move faster. This is what causes solids,liquids and gases to boil.
In an exam, they may ask you to choose an electrical appliance- How do you pick the best one?
- You might need to work out which appliance wastes/uses less energy or is more cost effective
- You may also need to consider the practicality of each appliance
- Think about advantages and disadvantages
How do you work out the cost of electricity?
To work out how much electricity will cost if used for a certain amount of time:
Units= kW x hours
To work out the cost of electricity:
Cost= Units x Price
