9.4 Heat and Energy Transfer

• Heat is a form of energy transfer that occurs due to a temperature difference between two objects or systems.energy
• Conduction is the transfer of heat through direct contact
• What are the three primary methods of heat and energy transfer?

  Conduction, convection, radiation
• What type of electromagnetic wave is primarily responsible for radiation heat transfer?

  Infrared light
• In conduction, heat is transferred through direct contact as kinetic energy is passed from molecule to molecule
• Order the three mechanisms of heat transfer based on the type of energy transfer they use.

  1️⃣ Conduction: Kinetic energy passed molecule to molecule

  2️⃣ Convection: Movement of fluid

  3️⃣ Radiation: Electromagnetic waves
• Radiation does not require a medium to transfer heat.


  True
• Order the steps involved in heat transfer by convection.

  1️⃣ Warmer, less dense fluid rises

  2️⃣ Creates convective currents

  3️⃣ Distributes heat
• Match the heat transfer mechanism with its example:

  Conduction ↔️ Hot pan warming a stovetop

  Convection ↔️ Boiling water

  Radiation ↔️ Sunlight warming Earth
• Air has the lowest thermal conductivity among the listed materials.


  True
• Specific heat is the heat required to raise the temperature of one gram of a substance by one degree Celsius.


  True
• At thermal equilibrium, there is no net heat transfer between objects.


  True
• In the process of reaching thermal equilibrium, heat flows from the hotter object to the cooler object.
• Boiling involves the absorption of the latent heat of vaporization.
• Sunlight warming the Earth is an example of heat transfer through radiation.
• Heat is the same as temperature, which measures the average kinetic energy of particles.

  False
• Convection involves the movement of fluids, such as liquids or gases, to transfer heat.


  True
• In conduction, kinetic energy is transferred from molecule to molecule
• Order the steps involved in heat transfer by convection:

  1️⃣ Hotter, less dense fluid is heated

  2️⃣ Heated fluid rises

  3️⃣ Cooler, denser fluid sinks

  4️⃣ Convective current is created
• Convection requires a medium such as a fluid to transfer heat.


  True
• Match the heat transfer mechanism with its definition:

  Conduction ↔️ Heat transfer through direct contact

  Convection ↔️ Heat transfer by fluid movement

  Radiation ↔️ Heat transfer through electromagnetic waves
• Match the heat transfer mechanism with its primary requirement:

  Conduction ↔️ Direct contact

  Convection ↔️ Fluid movement

  Radiation ↔️ Electromagnetic waves
• Convection can occur in a vacuum.

  False
• Thermal conductivity is defined as the rate at which heat passes through a substance per unit area per degree Celsius of temperature difference
• Match the material with its thermal conductivity (W/m·K):

  Silver ↔️ 429

  Aluminum ↔️ 237

  Wood ↔️ 0.17
• Match the material with its specific heat (J/g·°C):

  Water ↔️ 4.184

  Aluminum ↔️ 0.900

  Iron ↔️ 0.450
• Match the thermal equilibrium concept with its characteristic:

  Thermal Equilibrium ↔️ Objects at the same temperature

  Temperature Differences ↔️ Heat flows from hotter to cooler objects

  Stable State ↔️ Dynamic process towards equalization
• A hot cup of coffee cooling to room temperature is an example of thermal equilibrium.


  True
• Conduction is the transfer of heat through direct contact.

  True
• A hot metal pan warming a stovetop is an example of conduction.

  True
• Thermal conductivity measures a material's ability to conduct heat.


  True
• Specific heat is the amount of heat required to raise the temperature of one gram of a substance by one degree Celsius.
• Radiation transfers heat through electromagnetic waves without needing a medium.
• What is the formula for heat capacity?

  $C =$$\frac{Q}{\Delta T}$
• What is the net heat transfer at thermal equilibrium?

  Zero
• At thermal equilibrium, heat flows from the hotter object to the cooler
• During phase transitions, temperature remains constant while energy is absorbed or released.

  True
• When water boils, it absorbs the latent heat of vaporization without changing temperature.


  True
• In the Stefan-Boltzmann law, the symbol ε represents emissivity
• There are three main mechanisms of energy transfer: conduction, convection, and radiation