Specific heat capacity and convection and conduction Flashcards
What is specific heat capacity?
The amount of energy needed needed to raise the temperature of 1kg of a substance by 1 degrees
What is formula for specific heat capacity?
Change in thermal energy= mass* Specific heat capacity * temperature change
What equation links power, energy transferred and time?
Power= Energy transferred/time
What equation links power, work done and time?
Power= work done/time
What is the conservation of energy principle?
Energy can be transferred usefully, stored or dissipated, but can never be created or destroyed
What is conduction?
The process where vibrating particles transfer energy to neighbouring particles
What state of matter does conduction occur in?
Solids
What are the steps of conduction?
1.Energy transferred to an object by heating is transferred to the thermal store of energy.This energy is then shared across kinetic energy stores of the particles
2.The particles in the part of the object begin to vibrate more and the rate of collisions increases.These collisions cause energy to be transferred between the particles kinetic energy stores
What is thermal conductivity?
A measure of how quickly energy is transferred between particles
What is convection?
Where energetic particles move from hotter to cooler region
What states of matter does convection occur in?
Liquids and gases
Describe convection
The particles are able to move, and when the substance is heated the particles move faster, causing the density to decrease.
The the warmer and less dense regions will rise above the denser and cooler regions. If there is a constant heat source a convection current can be created.
How can you reduce unwanted energy transfers?
Through lubrication or insulation
What is the efficiency equation?
Energy= useful output energy transfer/ total input energy transfer
Energy= useful power output/total power input
