Many thermometers today are electronic. Let’s see how different types of electronic thermometers are made and what are their working principles. 1 ) Most contain a tiny bead of a semiconducting material whose resistance varies with temperature. The bead is called a thermistor, or thermal resistor. 2 ) Others contain a tiny semiconducting diode. The […]

# Thermal Physics_21

## How kinetic theory of gases explains the gas laws?

The kinetic theory can explain the behavior of gases. The kinetic theory of gases explains the gas laws, as well. Here, we will study a few of such explanations. a) How kinetic theory of gases explains the Cause of gas pressure? All the molecules in a gas are in rapid random motion, with a wide […]

## Gas constants and their relationships

Gas Constants & their values The Avogadro constant (NA) = 6.02 × 1023 particles per mole The molar gas constant or universal gas constant (R) = 8.31 J mol−1 K−1 The Boltzmann constant (kb) = 1.38 × 10−23 J K−1 Gas constants and their relationships For an ideal gas of n moles and N molecules:number […]

## How to derive the value of R (Universal Gas Constant)

The Combined Gas Law or Gas Equation is as follows: PV / T = constant (K) ……… (1) The value of this constant K changes if the volume of the gas changes. (so, not a constant actually) Hence, a new constant kb is brought in, so that K = N kb, where n = number […]

## Describing phase change in terms of molecular behaviour

In this post, we will describe the change of state (phase change) in terms of molecular behavior. When solids that do not melt are heated, the thermal energy supplied overcomes some intermolecular forces and therefore increases some molecular potential energies. But most of the thermal energy supplied increases the average kinetic energy of the molecules […]

## Graphs for state change or phase change | change of state – graphs

In this post, we will study the Graphs for state change (phase change graphs or change of state graphs). We have already studied the keywords related to the state change or phase change here. Sketching and interpreting phase change graphs (change of state – graphs) The three change of phase graphs (drawn below) all have […]

## Thermodynamics – Formula bank

In this post, we present 30 formulas from the Thermodynamics chapter (class 11 physics). This formula bank is going to help you to find the formulas in a single place. formulas from Thermodynamics

## Change of state – some keywords & definitions

In this post, we defined some keywords related to ‘change of state’ or Phase change. These words include terms like critical point, triple point, etc. The three states of matter that you have considered are solid, liquid, and gas. Each of these states of matter can be considered as a phase. A phase change occurs […]

## Latent heat and specific latent heat – definitions & concepts

In this post, we will discuss the fundamentals of latent heat and specific latent heat. latent heat – definition Latent heat is the amount of energy released or absorbed by a substance during a change of state that occurs without a change in temperature. The amount of energy associated with the phase change is called […]

## Internal Energy of a System – revision notes

On the basis of the kinetic theory of matter, we can discuss the concept of internal energy as the sum of the energies of individual components/constituents. This includes kinetic energy due to their random motion and their potential energy due to interactions amongst them. Let us now discuss these. Internal energy is the sum of […]

## Carnot cycle processes of Carnot engine

The Carnot cycle represents the cycle of processes for a theoretical heat engine with the maximum possible efficiency. Such an idealized engine is called a Carnot engine. Here in this post, we present a brief idea of the Carnot cycle processes, Carnot engine efficiency, and also we solve here a numerical problem related to the […]

## How do refrigerators and air conditioners work? | work and heat flow

In this post, we will briefly discuss (1) how refrigerators work, & (2) How Air conditioners work. Work and Heat flow diagram of refrigerator and air-conditioner is also presented here. How do Refrigerators work – in brief Here are the steps followed in a refrigerator Refrigerators work by causing the refrigerant circulating inside them to […]

## The Carnot Engine

In this post, we will discuss the concepts of the Carnot engine. We will also cover subtopics like Assumptions made for the Carnot engine, the existence of the Carnot engine(if possible?), Laws of Thermodynamics & the Carnot Engine, Efficiency & temperature, etc. During the early 19th century maximizing the efficiency of the heat engine was an […]

## What is the third law of thermodynamics?

What is the third law of thermodynamics?The third law of thermodynamics states that absolute zero, the lowest possible temperature, can never be reached. The entropy of a system is zero at absolute zero. A procedure can remove a portion of the entropy, but not all of it. Thus it would take an infinite number of […]

## Entropy as Probability – most disorder state is the most probable one

In this post, we will discuss how we can consider Entropy as Probability. We have already covered entropy (disorder) when we discussed the 2nd law of Thermodynamics. There is a statistical explanation of entropy that says that the most disorder state is the most probable one. We will present this with the example of the […]

## Heat Engines

This post talks of an important topic of the Thermodynamics chapter of Physics. We talk here about Heat Engines, their definition, examples of heat engines, internal combustion engines, internal combustion process, formulas and diagrams of heat engine, efficiency formulas of heat engines, etc. Heat Engine – definition Any device that uses heat (thermal) energy to […]

## The Second Law of Thermodynamics & Entropy

To understand the Second Law of Thermodynamics it’s essential to understand the concept of Entropy. Once we get an idea of entropy with an example, we will discuss 3 different forms or statements of the 2nd law of thermodynamics. [Readers also viewed these: zeroth law of thermodynamics andfirst law of thermodynamics ] Entropy or disorder […]

## P–V diagram & calculation of work done

In this post, we will discuss how the P-V diagram can help us to calculate the work done by a system or on a system. We will derive the equation of work done in terms of pressure and volume. We will solve a few numerical problems as well based on P-V diagrams. Setup to get […]

## Heat capacity & Specific heat capacity – explanation & measurement

Reference: 1 great notes IB physics study guide Oxford IB diploma program bt Tim Kirk

## Conduction of Heat – study notes

Conduction is a mode of transmission of heat where heat flows from the hot end to the cold end and particles of the medium simply oscillate but do not leave their place. Conduction of Heat has the following characteristics: Medium is necessary for conduction. It is a slow process. The path of heat flow may […]

## Heating effect of electric current class 10 – formulas & Numerical

In this post, we will discuss the Heating effect of electric current (class 10) and list down the Heating Effect formulas or Equations of electric power and energy. And, then we will solve a bunch of numerical problems as well using these formulas. Heating effect of current formulas for power and energy The power P […]

## Numerical problems on the first law of thermodynamics

In this post, we will solve a few numerical problems using the First Law of Thermodynamics. Numerical problems on first law of thermodynamics Question number 1) Complete the values in Table 1 (all values are in kJ). Note that: W = 6 kJ is the work done on the system. Solution: As per the data […]

## Thermodynamic energy model & First law of thermodynamics

In this post, we will draw the Thermodynamic energy model to relate heat in, work done on the system, heat out, and work done by the system. Before that, we will discuss the example of a bike pump and mention the First law of thermodynamics. Heating up a Bike pump by increasing its internal energy […]

## Specific latent heat of vaporization – revision notes

Latent heat is needed to change a liquid into a vapour (during vaporization). Let’s discuss on Specific latent heat of vaporization in detail. role of latent heat of vaporization If liquid molecules are to overcome the forces holding them together and gain the freedom to move around independently as gas molecules, they need a large […]

## Specific latent heat of fusion – REVISION NOTES

The specific latent heat of fusion (lf) of a substance is the quantity of heat needed to change the unit mass of it from solid to liquid without temperature change. role of latent heat of fusion The kinetic theory explains latent heat of fusion as being the energy that enables the molecules of a solid […]

## What is a Bimetallic strip & what are its uses?

If equal lengths of two different metals, such as copper and iron, are riveted together so that they cannot move separately, they form a bimetallic strip (Figure 1). When heated, copper expands more than iron, and to allow this the strip bends with copper on the outside (Figure 2). If they had expanded equally, the […]

## Conduction, Convection, & Radiation – Energy transfer during heating & cooling

There are three different processes through which energy can be transferred during heating and cooling: conduction, convection, and radiation. Conduction is the transfer of heat through a substance as a result of collisions between neighbouring vibrating particles. Convection is the transfer of heat through a substance as a result of the movement of particles between […]

## Internal energy of a substance – Definition and Different forms

To describe the total energy of the molecules in a substance, we need to take into account both the kinetic energies and the potential energies. This is called the internal energy of the substance and is defined as follows: The internal energy of a substance is the sum of the total random kinetic energies and […]

## Temperature scales and absolute temperature

The temperature scales that we use today were designed for simplicity and easy reproduction. The Celsius temperature scale is used throughout the world and is a good example of how the effective communication of data between individuals and countries is dependent on an agreed system of units. For historical and cultural reasons, there a few […]

## Molecular theory of solids, liquids, and gases to explain their shape and volume

The molecular theory of solids, liquids, and gases explains the reason behind their shape and volume. Let’s find out how in the next paragraph. – In solids, the molecules (or atoms, or ions) are held close together by strong forces, usually in regular patterns. The molecules vibrate about their mean positions. See Figure 2 (left […]

## The gas laws | Statement, Formula, graph of Charles’ law, Boyle’s Law & Pressure law

The gas laws tell us the relationship between pressure, temperature, and volume of gases. The gas laws can be stated in a convenient form for calculations when absolute temperatures are used. The laws we are going to cover here are (1) Charles’ Law (2) Pressure Law, and (3) Boyle’s Law. Charles’ law | Statement of […]

## How to explain the anomalous expansion of water in simple words?

In the case of fluids, with the rise of temperature, the volume increases. Therefore, the density decreases. But, water expansion shows an anomalous behavior for a specific temperature zone. As we explain this behavior we will get to know why water has its maximum density (and hence minimum volume) at 4°C. Heating of water: Water […]

## Thermal conductivity definition, formula, and Thermal conductivities of some common materials

Thermal conductivity definition, formula, and Thermal conductivities of some common materials, factors affecting thermal conductivity

## What are Heat Capacity and Specific Heat? | comparison | Specific Heat Data table | numerical problems solved

we will discuss Heat Capacity and Specific heat, their relationship, comparison, Specific heat data tables, and formula. We will also solve a few numerical problems based on the formulas.

## First Law of Thermodynamics – so easy to understand?

Here in this post, we will cover the first law of thermodynamics. It basically talks about the effects of heat transfer in terms of internal energy and work done. As this law is based on the concept of internal energy, we will briefly cover this before stating the 1st law of thermodynamics. Internal Energy – […]

## Thermal Conductivity Derivation| Dimension of thermal conductivity

The thermal conductivity of a material (designated as k) is the measure of how quickly heat energy is transferred or conducted from one end of the material to the other end. In this post we will work on the derivation of the thermal conductivity formula first, then we will find the dimension of thermal conductivity as well. Derivation […]

## Zeroth Law of Thermodynamics and thermal equilibrium

This post is on Zeroth Law of Thermodynamics. To discuss this we will begin with a briefing on the definition of Thermodynamics and the concepts of Thermal Equilibrium in the context of Thermodynamics. The Zeroth Law of Thermodynamics throws light on a major condition of thermal equilibrium among systems. Thermodynamics – define it Thermodynamics is […]