Understanding zeroth law of thermodynamics

Let us learn Zeroth Law of Thermodynamics

Let us consider two systems A and B separated from each other by thermally insulated wall (one that conducts no heat), but each being in contact of a third system C through a (diathermic) wall which permits heat to pass. Then the system A will be in thermal equilibrium with system C and similarly system B will also be in thermal equilibrium with system C.
Now if the adiabatic wall between systems A and B is replaced by a diathermic wall, experiments show that no further change occurs in a system A and B indicating thereby the system A was also in thermal equilibrium with B, This important experimental fact leads to the following general conclusion. you can also get help with density of metals . This statement is called the zeroth law of thermodynamics and forms the basis of concept of temperature. All these three systems can be said to possess a property that ensure their being in thermal equilibrium with one another.

Properties of Light

Today's topic is properties of light.

The term light sometimes refers to electromagnetic radiation of any wavelength, whether visible or not.

Light is electromagnetic radiation that has properties of waves. The electromagnetic spectrum can be divided into several bands based on the wavelength of the light waves

There are two properties of light

Reflection and Refraction.


Dispersion of Light

The fact that refractive indices differ for each wavelength of light produces an effect called dispersion of light. This can be seen by shining a beam of white light into a triangular prism made of glass. White light entering such a prism will be refracted in the prism by different angles depending on the wavelength of the light.

When light enters a transparent material some of its energy is dissipated as heat energy, and it thus looses some of its intensity. When this absorption of energy occurs selectively for different wavelengths of light, they light that gets transmitted through the material will show only those wavelengths of light that are not absorbed. The transmitted wavelengths will then be seen as color, called the absorption color of the material.

FORMS OF ENERGY

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Energy (is a quantity that can be assigned to every particle, object, and system of objects as a consequence of the state of that particle, object or system of objects. Different forms of energy include kinetic, potential, thermal, gravitational, sound, elastic, light and electromagnetic energy.

Energy transformation in the universe over time are characterized by various kinds of potential energy that has been available since the Big Bang, later being "released" (transformed to more active types of energy such as kinetic or radiant energy), when a triggering mechanism is available.

Different forms of energy.

There are different forms of energy, all of which measure the ability of an object or system to do work on another object or system. Listed below are some forms of energy.

Kinetic Energy

Potential energy

Thermal or heat energy

Chemical energy

Electrical energy

Electrochemical Energy

Electromagnetic Energy

Sound Energy

Nuclear Energy

DEFINITION OF PHYSICS

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The science of nature, or of natural objects; that branch of science which treats of the laws and properties of matter, and the forces acting upon it; especially, that department of natural science which treats of the causes (as gravitation, heat, light, magnetism, electricity, etc.) that modify the general properties of bodies; natural philosophy.

Definition of Physics: The branch of science concerned with the study of properties and interactions of space, time, matter and energy.

Physics is considered to be the most basic of the natural sciences. It deals with the fundamental constituents of matter and their interactions as well as the nature of atoms and the build-up of molecules and condensed matter. It tries to give unified descriptions of the behavior of matter as well as of radiation, covering as many types of phenomena as possible. In some of its applications, it comes close to the classical areas of chemistry, and in others there is a clear connection to the phenomena traditionally studied by astronomers. Present trends are even pointing toward a closer approach of some areas of physics and microbiology.

There are different topics in Physics like Waves, types of waves, static electricity, reflection-and-refraction, etc…

WHAT IS KINETIC ENERGY

The kinetic energy of an object is the extra energy which it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its current velocity. The kinetic energy of a single object is completely frame-dependent (relative). The kinetic energy of an object is directly proportional to the square of its speed. The kinetic energy equation is used frequently in conjunction with other forms of energy. Due to the law of conservation of energy, the total energy in a closed system will remain constant.
Kinetic energy is an expression of the fact that a moving object can do work on anything it hits; it quantifies the amount of work the object could do as a result of its motion. The total mechanical energy of an object is the sum of its kinetic Energy and potential energy. An object which has motion - whether it be vertical or horizontal motion - has kinetic energy.

FORMS OF KINETIC ENERGY:

There are many forms of kinetic energy.

Vibrational Energy: It is the energy due to Vibrational motion.
Rotational Energy: It is the energy due to rotational motion.

Translational Energy: It is the energy due to motion from one location to another.

Let us now see one solved example on how to calculate Kinetic Energy.

How much kinetic energy does an object have if its mass is 5.0 kg and it is moving at a speed of 4.0 m/s? EK = (1/2)mv2 EK = (1/2)(5.0 kg)(4.0 m/s)2 EK = 40 J

Solution:

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E_K = (1/2)mv²

E_K = (1/2)(5.0 kg)(4.0 m/s)²

E_K = 40 J

Waves

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A wave is a disturbance that travels through space and time, usually by transference of energy. There are two types of waves. Waves are described by a wave function that can take on many forms depending on the type of wave. A mechanical wave is a wave that propagates through a medium due to restoring forces produced upon its deformation. Waves travel and transfer energy from one point to another, often with no permanent displacement of the particles of the medium that is, with little or no associated mass transport.

TYPES OF WAVES:

Waves appear in various forms such as water waves, light waves and sound waves. Listed below are the types of waves.

Longitudinal Wave: When the particles of the medium are displaced parallel to the direction of the propagation of the wave, it is called a longitudinal wave.

Transverse Wave: When the particles of the medium are displaced perpendicular to the direction of the propagation of the wave, it is called a transverse wave.

Human Heart

Did you give your friends valentines and little heart-shaped candies on Valentine's Day? Your have you ever blessed any one form the bottom of your heart or may be cursed someone from the bottom of your heart? We have been hearing that many feelings come from the heart. This simply means that Heart is the most important part in a Human body.

The human heart is a pear-shaped structure about the size of a fist. The heart is an amazing organ. It is responsible for supplying the body with oxygenated blood. Each time the heart beats, it exerts a pressure on the veins and arteries called Blood Pressure. The heart is one of the most important organs in the entire human body. It is really nothing more than a pump, composed of muscle which pumps blood throughout the body, beating approximately 72 times per minute of our lives.
How does the heart beat?

Before each heart beat, the heart fills with blood. Then its muscle contracts to squirt the blood along. When the heart contracts, it squeezes — try squeezing your hand into a fist. That's sort of like what the heart does so it can squirt out the blood. The Heart does this all day and all night, all the time.

What is Physics?

The nature around us is colourful and diverse. It contains phenomena of large varieties. The winds, the sands, the waters, the planets, the rainbow, heating of objects on rubbing, the function of human body, the energy coming from the sun and the nucleus...... there are large number of objects and events taking place around us.

Physics is the study of nature and its laws. We expect that all these different events in nature take place according to some basic laws and revealing these laws of nature from the observed events is Physics. Physics is concerned with the basic rules which are applicable to all domains of life. Thats is why physics is known as real since it is the study of nature. No one has been given the authority to frame the rules of physics. We only discover the rules that are operating in nature. Some of the great physicists are Aryabhat, Newton, Einstein and Feynman.

Spherical Mirrors

A spherical mirror is a mirror which has the shape of a piece cut out of a spherical surface. A spherical mirror is simply a piece cut out of a reflective sphere. Its center of curvature, C, is the center of the sphere it was cut from. R, the mirror's radius of curvature is the radius of the sphere. The focal point F (the point where parallel rays are focused) is located half the distance from the mirror to the center of curvature.

Types of Spherical Mirrors:

• Concave Mirrors
• Convex Mirrors

Concave Mirror: If the mirror's inside surface is reflective, the mirror is concave.Concave mirrors can form either real or virtual images, depending on where the object is. The Image below is an example of Concave Mirror.



Convex Mirror: If the mirror's outside surface is reflective, it's a convex mirror. A convex mirror can only form virtual images. A real image is an image that the light rays from the object actually pass through; a virtual image is formed because the light rays can be extended back to meet at the image position, but they don't actually go through the image position.The Image below is an example of Convex Mirror