Showing posts with label cloud chamber. Show all posts
Showing posts with label cloud chamber. Show all posts

PHYSICS DICTIONARY

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Climate

The climate where you live is called regional climate. It is the average weather in a place over more than thirty years. To describe the regional climate of a place, people often tell what the temperatures are like over the seasons, how windy it is, and how much rain or snow falls. The climate of a region depends on many factors including the amount of sunlight it receives, its height above sea level, the shape of the land, and how close it is to oceans. Since the equator receives more sunlight than the poles, climate varies depending on distance from the equator.


Clipping Circuit

Circuit with which the waveform is shaped by removing a portion of applied wave is known as clipping circuit.


Clock

Mechanical / electrical device used for measuring and recording time.


Closed System

System which cannot exchange matter with surroundings but only exchanges energy with surroundings.


Closely Packed Structure

Crystal structures which have high atomic packing fraction. There are two types of closely packed structures i) Hexagonal closely packed   ii) Face centered closely packed.


Cloud Chamber

The first instrument which made possible visual observation of tracks of charged particles in their passage through matter was Wilson’s cloud chamber. The principle of the chamber is that super cooled vapor condenses only on charged particles and if charged particles are not present, they remain in vapor phase. If saturated vapor in a chamber is suddenly subjected to an adiabatic expansion, there will be an increase in volume which produces cooling rendering saturated vapor to a super saturated unstable state. If some ions are present in the chamber then condensation takes place on them. Ions are produced by passage of high energy particles through chamber leading to tracks. 


Cloud

Visible mass of fine water droplets, ice particles suspended in atmosphere at high altitudes above sea level.


Cluster

 Group of galaxies is called as cluster.


Co- axial System of Lenses

A combination of lenses having a common principal axis is called a co- axial system of lenses.


Coaxial Cable

Cables having construction of coaxial geometry in which central conductor is separated from braid by insulator  


Cobalt-60

This is a radioactive element formed by bombarding stable isotope of Cobalt i.e. Co59 with neutrons. Cobalt-60 has half life of 5.3 years which decays by emitting beta followed by gamma rays. In 99.87% decays, the gamma rays are emitted with 1.17 MeV and in other cases with 1.33 MeV.


Coefficient of Areal Expansion

The ratio of increase in area per degree rise of temperature to the original area of solid.


Coefficient of Contraction

It is defined as the ratio of the minimum cross-sectional area of a jet of liquid discharging from an orifice to the area of the orifice.


Coefficient of Linear Expansion

The ratio of increase in length per degree rise of temperature to the original length of solid.


Coefficient of Mutual Inductance

When two inductors are coupled, the mutual inductance is proportional to square root of product of two inductances. The coupling coefficient has value between 0 and 1.


Coefficient of Restitution

The coefficient of restitution is a measure of the elasticity in a one-dimensional collision. It could be defined as the ratio of the relative velocity after impact to the relative velocity before the impact of two colliding bodies.


Coefficient of Self Inductance

It is a quantity that relates magnitude of self induced voltage in coil to the rate of change of current in the coil. Its SI unit is Henry.


Coefficient of Static Friction

It is proportionality constant between friction and normal force acting on the object over the surface.


Coefficient of Linear Expansion

The ratio of increase in length per degree rise of temperature to the original length of the solid.


Coefficient of Superficial Expansion

The ratio of increase in area per degree rise of temperature to the original area of the solid.


Coefficient of Volume Expansion

The ratio of increase in volume per degree rise of temperature to the original volume of the solid.

 

Coercive Field or Coercivity

In case of ferromagnetic or ferrimagnetic materials, a critical magnetic field must be applied in direction opposite to original field to reduce the magnetic flux density inside the specimen to zero, which is called coercive field and the phenomenon is called coercivity.


Coherence length

It is defined as the maximum distance up to which the pair of electrons (cooper pair) is correlated to produce superconductivity.


Coherence Source

The source which emits coherent waves with respect to both time & space is called coherent source.


Coherent Scattering

Type of scattering in which photon when interacts with matter excites atom and gets scattered.


Coherent Waves

Two light waves of same frequency having constant phase difference are known as coherent waves.


Cohesion

The force of attraction between molecules of same substance is called as cohesion.


Cohesive Energy of Crystal

Energy of crystal is lower than that of free atoms by an amount equal to the energy required to pull the crystal apart into a set of free atoms. This is called binding energy or cohesive energy.


Cold Neutrons

Neutrons having energy less than thermal neutrons are called as cold neutrons. 


Cold Welding

Welding in which fusion of metal is achieved only by applying pressure and no heat. 


Collimator

Device used for constraining the size and angle of spread of a beam of radiation or particles parallel to the tube axis to traverse required length.


Collision

It is the interaction between the bodies for a small time interval due to which the redistribution of momentum takes place.


Colloid

Particles substantially larger than atoms or ordinary molecules but too small to be visible to naked eye. In other words, any particle having dimension in range 10-7  To 10-3  cm. 

Pair Production - Conversion of Radiation into Matter

The cloud chamber experiments revealed that a Photon can give up its energy to materialize as two electrons of opposite charge. Certainly the Photon must have an energy of atleast 2mₑc² in order to produce a pair.

No photon, regardless of its energy, can produce a pair in a perfect vacuum.

Pair Production is strictly an Electromagnetic Process. It seems to occur mostly in the intense electric field near the nucleus rather than inside the nucleus.

At higher energies or with heavy targets it is typically reasonable to ignore the energy transferred to target, so that nearly all energy from Photon goes to electron-positron pair.

Energy equation

h𝜈 → 2mₑc²+E1+E2

holds approximately.

 mₑc²rest energy of each electron

 E1, E2 → Kinetic Energies of particles

 The heavier the target, the more nearly the equation is satisfied. 

Pair Production can occur in the vicinity of an electron.