P1 - Energy Flashcards
What is conduction
Heat is directly transmitted through the material of a substance.
What is a good conductor
Metal
What is a poor conductor
Non metals (insulation)
What is convection
A change in density causes particles to move from hotter to colder/cooler regions
Where does convection occur
In gases and liquids
What happens to the air in convection
Hot air rises and cool air falls
What is a latent heat
The energy transferred to or from a substance when it changes state
What 4 things happen when a substance is heating
- Temperature increases.
- Kinetic energy increases.
- potential energy is constant.
- Internal energy increases.
What is internal energy
The energy stored by the particles of a substance
What happens to kinetic energy if the temperature of a substance is increased
The total kinetic energy of the particles increase and so the internal energy also increases
What is the equation for weight
Mass x gravity (9.8 on earth)
What is the equation for elastic potential energy (EPE)
1/2 ke2
What is the equation for kinetic energy
1/2 mv^2
Equation for GPE
Mgh
Mass x gravity x height
What is the equation for power
Energy ÷ time taken
What is 1 watt equal to (derived units)
1 joule per second
Work done equation
Force x distance
What is work done
When any object is moved around eg energy is supplied
Efficiency equation
Useful energy given out ÷ energy put in x 100
Work done is also classed as
Energy transferred
What is an efficient device
A device where most of rhe energy is usefully transformed
What is the most common waste energy
Heat energy given to the surroundings
What is waste energy
Energy that is transformed to either the wrong place or wrong form
What is useful energy
The energy is transferred to where it is wanted in the form delivered
Nine types of energy
Kinetic Sound Light Thermal Electrical Gravitational potential. Elastic potential. Chemical. Nuclear
How energy can be transferred
From place to place OR from form to form
What happens when a substance changes state
- Temperature is constant.
- kinetic energy is constant
- potential energy is increased
- internal energy is increased
What factors affect how much energy must be gained by an object as its temperature increases
- temperature increases
- mass
- material
How to work out specific latent heat and what is it measured in
Energy ÷ mass j/kg
How do non metals conduct
As a non metal is heated at one end, the atoms near the heat source gain kinetic energy and vibrate more and collide with each other so the energy is passed on.
What is specific heat capacity
The amount of energy required to raise 1kg of material by 1°c
What is the equation for specific heat capacity
Specific heat capacity = energy ÷ mass x temp
How do metals conduct
When a metal is heated, free electrons gain kinetic energy so they move faster and diffuse through the metal, energy is transferred when electrons collide with other electrons or ions
