Thermal energy unit, test, answers
1. What is the SI unit of thermal energy?
Answer: The SI unit of thermal energy is the joule (J).
2. Define thermal energy.
Answer: Thermal energy is the total internal energy of a system arising from the random motion of its particles. It represents the sum of the kinetic and potential energy of the particles in a substance.
3. How is thermal energy related to temperature?
Answer: Temperature is a measure of the average kinetic energy of particles in a substance, whereas thermal energy represents the total energy of all particles. So, thermal energy is directly related to temperature, as an increase in temperature leads to an increase in thermal energy.
4. What is specific heat capacity?
Answer: Specific heat capacity, also known as specific heat, is the amount of heat energy required to raise the temperature of a specific mass of a substance by 1 degree Celsius (or 1 Kelvin).
5. What is the formula to calculate thermal energy?
Answer: The formula to calculate thermal energy is given by:
Thermal Energy = Mass × Specific Heat Capacity × Change in Temperature
6. What is the zeroth law of thermodynamics?
Answer: The zeroth law of thermodynamics states that if two systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other. This allows for the definition of temperature and serves as the foundation for thermal energy exchange.
7. How does thermal energy transfer occur?
Answer: Thermal energy transfer can occur through three main processes: conduction (direct particle-to-particle transfer within a substance), convection (transfer through the movement of a fluid), and radiation (transfer through electromagnetic waves).
8. How does insulation affect thermal energy transfer?
Answer: Insulation materials are used to minimize the transfer of thermal energy by reducing conduction and convection. Good insulation materials have low thermal conductivity to prevent energy transfer, thus helping to maintain desired temperatures.
9. What is the first law of thermodynamics?
Answer: The first law of thermodynamics, also known as the law of energy conservation, states that energy cannot be created or destroyed, but it can be converted from one form to another or transferred between systems.
10. Give an example of a device that converts thermal energy into mechanical energy.
Answer: An example of a device that converts thermal energy into mechanical energy is a heat engine, such as an automobile engine. The combustion of fuel raises the temperature, and this thermal energy is then converted into mechanical work through the engine's pistons.