Physics 1a Flashcards
(15 cards)
What is the formula for specific heat capacity?
Energy transferred= mass*specific heat capacity *temperature change
What is specific heat capacity?
The amount of energy needed to raise the temperature of 1kg of a substance by 1 degree c
How do you calculate payback time?
Initial cost/annual saving
What types of heat transfer does cavity wall insulation protect from?
Convection, conduction, and radiation
What is a U-Value?
How fast heat can transfer through a material, the better the insulator, the lower the U-value
What types of heat transfer does loft insulation protect from?
Conduction and radiation
What increases the rate of evaporation?
Higher temperature, lower density, larger surface area, greater airflow over liquid.
What is conduction?
The process where vibrating particles pass on their extra kinetic energy to neighbouring particles
What is convection?
When more energetic particles move from the hotter region to the cooler region and take their energy with them. Convection currents are about changes in density.
What are the nine types of energy?
Electrical, light, sound, kinetic, nuclear, thermal, gravitational potential, elastic potential, and chemical energy.
How do you calculate efficiency?
Useful energy out/ total energy in
Or
Useful power out/ total power in
How do we calculate energy?
Power * time
What is energy usually measured in?
Joules
What is power measured in?
Watts or kilowatts
What are the advantages of LED lighting compared to traditional light bulbs?
More efficient and last longer
More expensive and don’t give out as much light
