Thermal Physics

Thermal energy is also known as 'heat energy' or simply 'heat'.

The coefficient of superficial expansion is the ratio of the increase in area of a body per degree rise in temperature to its unit area.

The process in which heat energy flows from a body at a higher temperature to another object at lower temperature is known as heating.

For any exchange of heat, the heat gained by the cold system is equal to heat lost by the hot system. This is known as the law of conservation of energy and is represented by the equation Heat gained = Heat lost.

Convection is a process of heat transfer where heat is transferred through the movement of a fluid, such as air or water. This occurs when a heated fluid expands and rises, while a cooler fluid contracts and sinks, creating a circular motion that transfers heat.

The relationship between Celsius and Kelvin temperature scales is given by the equation K = C + 273, where K is the temperature in Kelvin and C is the temperature in Celsius. This means that the temperature difference of 1°C is equal to that of 1K.

Temperature is the property which determines whether a body is in equilibrium or not with the surroundings.

A scalar quantity is a physical quantity that has only magnitude and no direction. Temperature is a scalar quantity as it only represents the degree of hotness of a body and does not have any direction associated with it.

Two or more physical systems or bodies are said to be in thermal equilibrium if there is no net flow of thermal energy between the systems. If two bodies are said to be in thermal equilibrium, then they will be at the same temperature.

The SI unit of temperature is kelvin (K).

Temperature is defined as the degree of hotness of a body.

Thermal energy is a form of energy which is transferred between any two bodies due to the difference in their temperatures.

There will be a transfer of heat energy from the hot body to the cold body until a thermal equilibrium is established between them.

The temperature measured in relation to absolute zero using the kelvin scale is known as absolute scale temperature.

A calorie is a unit of energy defined as the amount of heat energy required to raise the temperature of 1 gram of water by 1 degree Celsius.

Heat energy always flows from a system at higher temperature to a system at lower temperature.

The SI unit of heat energy absorbed or evolved is Joule (J). Heat energy is a form of energy that is transferred between two objects due to the difference in their temperatures.

Superficial expansion refers to the increase in area of a solid object due to heating. It occurs in all directions, unlike linear expansion which occurs only in one direction.

Explanation: Glass has a higher coefficient of linear expansion compared to other materials, which makes it more susceptible to thermal expansion.

The coefficient of linear expansion is a measure of how much a material will expand or contract in length when its temperature changes. It is defined as the ratio of the change in length per unit length per degree Celsius of temperature change. Therefore, option C is the correct answer.

Linear expansion refers to the increase or decrease in the length of an object due to changes in temperature. A metal rod increasing in length when heated is an example of linear expansion.

The extent of thermal expansion in solids depends on the nature of the object, i.e., the type of material, crystal structure, and bonding between atoms.

When heat energy is supplied to a substance, the temperature of the substance rises and it may change its state from solid to liquid or from liquid to gas. Additionally, the substance will expand when heated. The substance will not contract when heated.

For any exchange of heat, the heat gained by the cold system is equal to heat lost by the hot system.Heat gained = Heat lost.

A kilocalorie is a unit of energy defined as the amount of heat energy required to raise the temperature of 1 kilogram of water by 1 degree Celsius.