P1 Knowlege Organiser part B (1) Flashcards
(16 cards)
What does thermal conductivity tell you?
It tells you how quickly energy is transmitted through a material by thermal conduction.
Why is it important to reduce heat loss from buildings?
Heating bills can be expensive.
What is infrared radiation?
Infrared radiation is part of the electromagnetic spectrum.
What is a black body?
A theoretical object that absorbs 100% of the radiation that falls on it.
How can you test the thermal conductivity of rods made of different metals?
By using a set-up where one end of each rod is covered in wax and the other ends are heated equally. The faster the wax melts, the higher the thermal conductivity of the metal.
What factors affect the thermal conductivity of walls and roofs?
- The thickness of its walls and roof. 2. The thermal conductivity of its walls and roof.
What is a thermal insulator?
A material which has a low thermal conductivity.
What factors determine the rate of energy transfer through a material?
- The material’s thermal conductivity. 2. The temperature difference between the two sides of the material. 3. The thickness of the material.
What happens to an object’s temperature if it absorbs infrared radiation at a higher rate than it emits it?
The object’s temperature will increase.
What role do greenhouse gases play in Earth’s temperature?
They absorb infrared radiation emitted by the Earth’s surface and prevent it from escaping into space, re-emitting it back towards the surface.
What is specific heat capacity?
The amount of energy needed to raise the temperature of 1 kg of a substance by 1 °C.
What is the equation for calculating change in thermal energy?
∆E = m c ∆, where ∆E is change in thermal energy (J), m is mass (kg), c is specific heat capacity (J/kg°C), and ∆ is temperature change (°C).
What is a perfect black body?
An object that would not reflect or transmit any radiation and would also be a perfect emitter of radiation.
What human activities increase greenhouse gases?
Burning fossil fuels, deforestation, and livestock farming.
What factors affect the rate of heat loss from a building?
- Thickness of walls and roof. 2. Thermal conductivity of walls and roof. 3. Temperature difference between the two sides of the wall/roof.
What do you need to measure to determine the specific heat capacity of a substance?
The mass, temperature rise, and the time taken.
