Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Temperature is a physical quantity that expresses hot and cold. It is a measure of the average kinetic energy of the particles in a system.
Internal Energy is the total energy of all particles in an object (kinetic + potential), whereas Temperature only relates to the average kinetic energy.
The Kelvin scale () is the absolute temperature scale. is known as absolute zero, the theoretical temperature where all molecular motion stops.
The Celsius scale () is defined by the freezing point of pure water at and the boiling point at at standard atmospheric pressure.
A change in temperature of is equal in magnitude to a change of . Therefore, .
Thermal equilibrium is reached when two objects in contact no longer exchange net heat energy because they have reached the same temperature.
📐Formulae
💡Examples
Problem 1:
The surface of the Sun is approximately . What is this temperature in Celsius?
Solution:
Explanation:
To find the Celsius temperature from Kelvin, we use the subtraction constant (often rounded to in introductory courses).
Problem 2:
An object's temperature increases by . What is the increase in its temperature in degrees Celsius?
Solution:
Explanation:
Since the size of one unit on the Kelvin scale is identical to the size of one degree on the Celsius scale, any change in temperature () is the same for both scales.
Problem 3:
Convert to Fahrenheit.
Solution:
Explanation:
Using the conversion formula, we first multiply the Celsius value by (which is ) and then add to account for the different zero points of the scales.