Today, we will discuss how x rays are produced? It is proved that whenever fast moving electrons strike a target material of high atomic number and high melting point x rays are produced. But what happen after the collision of electrons? Why and how x rays are produced then? Let us discuss it:

Consider any target material of high atomic number and high melting point. We all know that electrons in an atom placed in different shells or orbits. When fast moving electrons under the influence of high potential difference (that may vary from 10000 volts and above) strike the target material, most of the electrons will heat the target and almost 10% of the electrons will lead to production of x rays.

Protons and neutrons are placed in nucleus of the atom so nucleus is heavily positively charge. When fast moving electrons will pass through the target material, it will be attracted towards the positive nucleus (see figure). The velocity of electrons will decrease. Thus there will be rate of change of velocity means there will be retardation or negative acceleration. As per the classical physics, whenever electrons retard, energy will be released in the form of radiation.

This is also known as Bremsstrahlung (Braking or retarding Radiation), Brems– to brake and strahlung-radiation. In this case, the radiation released will have energy in the range of energy of X rays. This is known as continuum or continuous x rays
Let us derive the Duane – Hunt law also:

• Let v₁ – initial velocity of electron
• Thus E₁ = ½ mv₁²– initial energy
• Let v₂ – final velocity
• Thus E₂ = ½ mv₂²– final energy
• Thus change in energy due to retardation
• ½ mv₁² – ½ mv₂² = hγ
• Where h is Planck’s constant and γ is frequency of radiation emitted

If electrons suddenly stopped that is v2 = 0, then take v1 = v, then we will get x ray of maximum energy.

Then above equation becomes:

½ mv² = hγ_max

• Also as electrons gain energy or move due to potential difference (V), thus
• ½ mv² = eV
• Comparing above equations
• hγ_max = eV
• or hc/λ_min = eV
• or λ_min = hc/eV
• = 12400/V angstrom
• This is Duane-Hunt law or limit

It shows that wavelength of emitted x rays depends upon the potential difference only. More the potential difference, lesser will be the wavelength or vice versa.

I will discuss the graph or continuous x rays in my next article with characteristic x rays. If you have any doubt, please share as comment.

You can also see our youtube video about continuous x rays here:

The post Production or origin of Continuous X rays first appeared on Winner Science.

Let us today discuss about the two types of x rays on the basis of their energy:

soft x rays and hard x rays.

1. Soft x rays: As the name suggests, the x rays having lesser frequency, it means lesser energy (because energy is directly proportional to frequency) is known as soft x rays. As frequency is inversely proportional to wavelength, thus these soft x rays have more wavelength. These x rays have lesser penetrating power. The energy of soft x rays is lesser than 5 kilo electron volt.

2. Hard x rays: As the name suggests, the x rays having more frequency comparative to soft x rays, it means more energy (because energy is directly proportional to frequency) are known as hard x rays. As frequency is inversely proportional to wavelength, thus these hard x rays have lesser wavelength than soft x rays. These x rays have more penetrating power. The energy of hard x rays is may vary from 5 to 10 kilo electron volt.  These are the basic differences between soft and hard x rays. I hope you have understood the differences.

The post Difference between Soft X rays and Hard X rays first appeared on Winner Science.

In 1895, a scientist named Roentgen was doing experiment in his lab with cathode rays (fast moving electrons) using electric discharge tube. He observed a pattern on a plate or board covered with phosphorous was illuminated. He completely covered the board with black things but glow was again there.

I will discuss about the production of x rays in my coming lectures that is what happened in electric discharge tube now a days its modern version is known as coolidge tube.

Roentgen was convinced that this illumination was due to certain different reason. He investigated the reason and found that it was due to a new type of rays. As rays were unknown so it was then named as X rays (like in mathematics we say that unknown quantity is X).

In 1901, Roentgen got the Nobel prize for the same also. X rays in his honor are also known as Roentgen rays.

So by chance, there was discovery of x rays and I hope that you are now aware that why x rays are known as x rays.

The post Why X rays are known as X rays first appeared on Winner Science.