1.
What is the principle method called for warming gasses and liquids?
Correct Answer
A. Convention
Explanation
The correct answer is convection. Convection is the principle method for warming gases and liquids. It involves the transfer of heat through the movement of the heated substance itself, such as the rising of warm air or the circulation of heated water. Conduction, on the other hand, refers to the transfer of heat through direct contact between objects.
2.
What is the form of energy when heat moves between two objects through direct contact?
Correct Answer
A. Conduction
Explanation
Conduction is the correct answer because it refers to the transfer of heat energy from one object to another through direct contact. In this process, heat is transferred from the object with higher temperature to the object with lower temperature, resulting in the equalization of temperatures between the two objects. This type of energy transfer occurs through the collision of particles within the objects, causing the kinetic energy to be transferred from one particle to another.
3.
What is the movement of thermal energy through electromagnetic waves called?
Correct Answer
A. Radition
Explanation
Radiation refers to the transfer of thermal energy through electromagnetic waves. Unlike conduction or convection, radiation does not require a medium and can occur in a vacuum. It enables heat transfer from hotter to cooler objects by emitting infrared radiation, crucial for processes like heating the Earth by the Sun.
4.
How is sound energy carried?
Correct Answer
A. Waves
Explanation
Sound energy is carried through waves. When an object vibrates, it creates a disturbance in the surrounding medium, which then propagates as a wave. These waves carry the energy of the sound from the source to the receiver. The particles in the medium vibrate back and forth as the wave passes through, transferring the energy along the way. This is how sound energy is transmitted and perceived by our ears.
5.
What energy does our body use to walk or run?
Correct Answer
B. Mechanical
Explanation
Our body uses mechanical energy to walk or run. Mechanical energy is the energy possessed by an object due to its motion or position. When we walk or run, our muscles contract and produce force, which is then converted into mechanical energy to move our body. This energy allows us to perform physical activities and move from one place to another.
6.
Which statement accurately describes the concept of thermal conductivity?
Correct Answer
B. Thermal conductivity is the rate at which heat flows through a material due to a temperature difference across it.
Explanation
Thermal conductivity refers to the ability of a material to conduct heat. It quantifies how well a substance can transfer heat through it when there is a temperature gradient. Materials with high thermal conductivity allow heat to flow quickly through them, while those with low thermal conductivity resist heat flow.
7.
In the context of heat transfer, which principle governs the movement of thermal energy in fluids like air and water?
Correct Answer
A. Fourier's Law
Explanation
Fourier's Law states that the rate of heat transfer through a material is directly proportional to the temperature gradient and the cross-sectional area perpendicular to the direction of heat flow, while inversely proportional to the material's thermal conductivity. This principle governs the transfer of thermal energy in both solids and fluids like air and water.
8.
Which scenario best exemplifies the concept of thermal equilibrium?
Correct Answer
D. Two objects of different temperatures reach the same final temperature when brought into contact.
Explanation
Thermal equilibrium occurs when two objects at different temperatures are in contact with each other, and there is no net transfer of thermal energy between them. In this scenario, heat will flow from the hotter object to the cooler one until both reach the same final temperature.
9.
What is the primary method by which heat is transferred through a vacuum, such as in outer space?
Correct Answer
C. Radiation
Explanation
Unlike conduction and convection, which require a medium such as solids, liquids, or gases, radiation does not need a medium to transfer heat. In a vacuum like outer space, where there is no air or other material, thermal energy is transferred primarily through electromagnetic waves, a process known as radiation.
10.
Which factor has the greatest influence on the rate of convective heat transfer?
Correct Answer
B. Temperature difference between the object and its surroundings.
Explanation
The rate of convective heat transfer is largely determined by the temperature difference between the object and its surroundings. According to Newton's Law of Cooling, the greater the temperature difference, the faster heat is transferred by convection. Other factors such as surface area, material type, and distance also play a role but to a lesser extent compared to temperature difference.