B.1- Thermal Energy Transfers

Created by

Megan Butler

Cards (32)

What is the formula for density?
Density = mass / volume
What are the characteristics of solids?
Regular formation
Crystal lattice
Vibrate in a fixed position
Strong intermolecular forces
Higher density than liquids and gases (except water)
What are the characteristics of liquids?
Flow to take the shape of their container
Have a random arrangement of particles
Higher KE than solid form
Weaker intermolecular forces than solids
Lower density than solids
What are the characteristics of gases?
Flow and fill their containers
Particles arranged randomly and comparatively far apart
Weak intermolecular forces
Highest KE
Can be compressed
What does SHC stand for?
Specific Heat Capacity
What is the definition of specific heat capacity?
It is the amount of thermal energy required to raise the temperature of 1 kg of a substance by 1 K.
What is the formula for calculating SHC (c)?
Q = m c ΔT
What does heat capacity mean?
It refers to the amount of energy required to raise the temperature of an object by 1 K.
What are the three methods of thermal energy transfer?
Conduction (solids)
Convection (liquids)
Radiation (no medium)
How is thermal energy transferred through conduction?
It is transferred through collisions between particles in a material.
What is the relationship between heat transfer rate and cross-sectional area, temperature change and 1/length?
Proportional
What does the equation ΔQ = K A ΔT / Δx represent?
It represents the rate of energy transfer through conduction.
What is a black body in terms of radiation?
A black body is a perfect emitter and absorber of electromagnetic radiation.
How does temperature affect the intensity and peak wavelength of radiation emitted by a black body?
Higher temperatures result in higher intensity and shorter peak wavelengths.
What is Stefan's Law regarding luminosity (proportional to?)?
Luminosity is proportional to the fourth power of absolute temperature.
Luminosity is also proportional to the surface area of the black body.
What is the formula for calculating luminosity using Stefan's Law?
L = σ A T⁴
What is apparent brightness?
Amount of energy per second per unit area that arrives at a distance from that star (received intensity)
What is the formula for calculating apparent brightness?
I/B = L / 4πd²
What assumptions are made when calculating apparent brightness?
No radiation is absorbed or scattered between source and observer.
Star emits equal power in all directions.
Star is spherical.
What is temperature?
Measure of the average random KE of the particles in a substance
How do you calculate Kelvin from Celsius?
Add 273
What is internal energy?
Sum of the KE and PE of all the particles
What is heat?
The thermal energy transfer from a body of high temp. to low temp.
What is thermal equilibrium?
When two objects or systems are at the same temperature and there is no net transfer of heat between them.
What does a positive heat capacity (Q) mean?
Energy is transferred from the surroundings to the system
What does a negative heat capacity (Q) mean?
Energy is transferred from the system to the surroundings
What are these changes of state called?
Liquid to solid- fusing
Solid to liquid- melting
Gas to liquid- condensation
Liquid to gas- vaporisation
Gas to solid- deposition
Solid to gas- sublimation
When does a substance that is changing states experience changes in PE and KE?
KE- when cooling or warming
PE- when changing state
What is SLH of fusion?
Energy required to change the state of 1kg of a substance from solid to liquid without any temperature change
What is SLH of vaporisation?
Energy required to change the state of 1kg of a substance from liquid to gas without any temperature change
What is Wien's Displacement Law?
Tells us the wavelength of the maximum intensity for black bodies at a certain temperature
What is the value for Stefan Bolzmann's constant?
5.67 x 10⁻⁸ Wm⁻²K⁻⁴