Science: Heat Questions And Answers

Explanation
Heat is a form of energy and is measured in units of joules or kilojoules. Celsius and Kelvin are units of temperature, while milligrams is a unit of mass. Therefore, the correct answer is Joules/kilojoules.

Explanation
Temperature is a measure of the hotness and coolness of an object. It quantifies the degree of heat present in an object or the intensity of coldness. It is typically measured using a thermometer, which provides a numerical value indicating the temperature. Heat, on the other hand, refers to the transfer of thermal energy from one object to another. While temperature is a measure of the thermal state of an object, heat is the energy that is transferred due to temperature differences.

Explanation
Heat is transferred through particles. This is because heat is a form of energy that is transferred from one object to another by the movement of particles. When particles gain heat energy, they move faster and collide with neighboring particles, transferring the energy. This process continues until a thermal equilibrium is reached, where the particles have equal amounts of heat energy. Therefore, particles are responsible for the transfer of heat.

Explanation
The Kelvin scale starts at -273°C. This is because the Kelvin scale is an absolute temperature scale, where 0 Kelvin represents absolute zero, the point at which all molecular motion ceases. Absolute zero is equivalent to -273°C, so this is the starting point of the Kelvin scale.

Explanation
Heat is the transfer of energy. When there is a temperature difference between two objects, heat is transferred from the object with higher temperature to the object with lower temperature. This transfer of energy occurs through various mechanisms such as conduction, convection, and radiation. Therefore, energy is the correct answer as it accurately describes the nature of heat transfer.

Explanation
Scientists use the Kelvin scale for measuring temperature because it is an absolute temperature scale that starts at absolute zero, the point at which all molecular motion ceases. This makes it ideal for scientific calculations and comparisons. The Celsius scale is commonly used for everyday temperature measurements, while the Fahrenheit scale is used in the United States and a few other countries. However, the Kelvin scale is the most widely used by scientists due to its absolute nature.

Explanation
At absolute zero, particles have zero energy. This is because absolute zero is the lowest possible temperature, where all molecular motion ceases. At this temperature, particles do not possess any kinetic energy or potential energy, resulting in zero energy.

Explanation
Spark is less hot than a hot cup of tea. This can be explained by the fact that a spark is a small, brief burst of heat and light, whereas a hot cup of tea contains a larger amount of heat that is sustained over a longer period of time. Therefore, the spark would have a lower temperature compared to the hot cup of tea.

Explanation
When sound waves pass through a medium, they cause the molecules in the medium to vibrate. These vibrations generate friction between the molecules, leading to an increase in temperature. This phenomenon is commonly observed in high-intensity sound waves and can be harnessed in various applications, such as ultrasonic cleaning and medical treatments. Therefore, the statement "Yes" is correct as sound waves have the potential to generate heat.

Explanation
The three mechanisms of heat transfer are conduction, radiation, and convection. Conduction is the transfer of heat through direct contact between objects or substances. Radiation is the transfer of heat through electromagnetic waves, such as from the sun. Convection is the transfer of heat through the movement of fluids, such as air or water.