SCI8 Heat Energy and Transfer

What is the process of heat transfer through direct contact of particles in a substance?

• Reflection

• Conduction

• Convection

• Evaporation

Answer explanation

Conduction is the process of heat transfer through direct contact of particles in a substance.

Which type of material is a good conductor of heat?

• Metals

• Glass

• Wood

• Plastic

Answer explanation

Metals are good conductors of heat because they have free electrons that can easily transfer thermal energy.

Explain the process of convection as a heat transfer method.

• Convection is the transfer of heat through the movement of solid particles

• Convection is the transfer of heat through electromagnetic waves

• Convection is the transfer of heat through solid materials

• Convection is the transfer of heat through the movement of fluids (liquids or gases). When a fluid is heated, it becomes less dense and rises, while the cooler, denser fluid sinks. This creates a circular motion that transfers heat from one place to another.

Answer explanation

Convection is the transfer of heat through the movement of fluids. When a fluid is heated, it becomes less dense and rises, while the cooler, denser fluid sinks. This creates a circular motion that transfers heat from one place to another.

What is the main mode of heat transfer from the sun to the Earth?

• Conduction

• Convection

• The main mode of heat transfer from the sun to the Earth is radiation.

• Evaporation

Answer explanation

The main mode of heat transfer from the sun to the Earth is radiation.

How does insulation help in reducing heat transfer?

• Insulation increases heat transfer by allowing air to flow freely through its material

• Insulation has no effect on heat transfer

• Insulation reduces heat transfer by absorbing heat and releasing it slowly

• Insulation reduces heat transfer by trapping air pockets within its material, which slows down the movement of heat through conduction and convection.

Answer explanation

Insulation reduces heat transfer by trapping air pockets, slowing down heat movement through conduction and convection.

What happens to the particles in a substance when it is heated?

• The particles in a substance stop moving when it is heated.

• The particles in a substance shrink when it is heated.

• The particles in a substance change color when it is heated.

• The particles in a substance move faster and spread out when it is heated.

Answer explanation

When a substance is heated, its particles move faster and spread out.

Give an example of conduction as a heat transfer method.

• When a candle flame heats the air around it

• When a microwave heats food by radiation

• When a fan blows hot air around a room

• When a metal spoon is placed in a hot cup of tea, the heat from the tea is transferred to the spoon through conduction.

Answer explanation

Conduction is exemplified when heat is transferred from a hot cup of tea to a metal spoon placed in it.

What is the role of conductors in heat transfer?

• Conductors absorb heat and store it

• Conductors block the flow of thermal energy

• Conductors have no effect on heat transfer

• Conductors help in transferring heat by allowing the flow of thermal energy through them.

Answer explanation

Conductors facilitate heat transfer by allowing thermal energy to flow through them.

Explain the process of radiation as a heat transfer method.

• Radiation is the transfer of heat through electromagnetic waves, such as infrared radiation. It does not require a medium and can occur through a vacuum. The heat is emitted from a warmer object and absorbed by a cooler object.

• Radiation is the transfer of heat through the conversion of electrical energy into thermal energy.

• Radiation is the transfer of heat through the direct contact between two objects.

• Radiation is the transfer of heat through the movement of particles in a fluid medium.

Answer explanation

Radiation is the transfer of heat through electromagnetic waves, such as infrared radiation. It does not require a medium and can occur through a vacuum. The heat is emitted from a warmer object and absorbed by a cooler object.

What type of heat transfer occurs in a boiling pot of water?

• Convection and evaporation

• Conduction and evaporation

• Radiation and conduction

• Convection and radiation

Answer explanation

Boiling water involves convection and evaporation, where heat is transferred through the movement of liquid and the conversion of water into vapor.