Energy Transfer By Heating Flashcards
What is specific heat capacity?
The beefy required to raise the temperature of 1kg of the substance by 1 degrees celsius.
What is the unit of specific heat capacity?
J/kg degrees Celsius.
When energy is being transferred into your home by your home’s heating system what else is happening?
Energy is being transferred to the surroundings.
How does fibreglass insulate your house?
Fibreglass is a good insulator. The air between the fibre reduces the energy transferred by conduction.
How does cavity wall insulation reduce the rate of energy transfer through the outer walls of the house?
The cavity is the space between the two layers of brick that make up the wall. This type of insulation is pumped into the cavity. This insulator is better than the air it replaces. It tracks the air in small pockets, reducing the rate of energy transfer by conduction.
How does aluminium foil between the radiator and the wall work?
It reflects the radiation away from the wall and so reduces the rate of energy transfer by radiation.
How do double glazed windows work?
Between the two glass panes there is dry air or a vacuum. The thicker the glass and the lower its thermal conductivity is, the slower the rate of transfer of energy through it by conduction will be. Dry air is a good insulator, so it will reduce the rate of energy transfer by conduction. A vacuum prevents the energy transferring by convection.
What does the energy transfer per second through a layer of insulating material depend on?
The temperature difference across the material.
The thickness of the material.
The thermal conductivity of the material.
How can you reduce energy transfers?
The thermal conductivity of a material should be as low as possible.
The thickness of the insulating layer should be as thick as practically possible.
What do you absorb from the sun?
Infrared radiation.
What are infrared radiation and visible light waves part of?
The electromagnetic spectrum.
What happens to the wavelength of light across the visible spectrum from blue to red light.
The wavelength increases.
If the temperature of an object is high, what is its infrared radiation like?
It emits more infrared radiation in a given time.
What is black body radiation?
It’s an object that absorbs all the radiation that hits it. It doesn’t reflect or transmit any radiation. Also, it is the best possible emitter.
What does the earths temperature depend on?
The rate light and infrared radiation are:
Reflected back into space by the Earth’s atmosphere or Earth’s surface.
Emitter form the Earth’s surface and from the Earth’s atmosphere into space.
