MACH - WHAT IS IT?

The Concord is an airliner that can get to a Supersonic speed of about Mach 2+

Have you heard or read of a unit called Mach?
It is a derived unit of speed, named after the physicist, Ernst Mach.
The mach value for any magnitude of velocity can be gotten by dividing the velocity with the speed of sound in air (~ 330m/s). Then the value you get, is now a mach.
Note: unlike other units in physics, the magnitude is read or written after mach.
E.g. Mach 2 or M 2.

MACH VALUES
Different Ranges or values of Mach has a name. They are;
1. Subsonic: M < 1
2. Tran-sonic: M = 1
3. Supersonic: 1 < M < 3
4. High Supersonic: 3 < M < 5
5. Hyper-sonic: 5 < M < 10
6. High Hyper-sonic: 10 < M < 25
7. Re-entry Speed: M < 25

The value of M, is used in fluid Mechanics (a branch of physics) to model the properties of an object as it moves through a fluid like air.
This helps to know the actual drag and lift forces acting on the surface of the moving body and in turn, it helps Aerodynamics engineers to produce efficient and safe designs like the ones your see in Rockets and Jets.

It all starts with PHYSICS.

Hope you enjoyed it? Because PHYSICS IS FUN.

Feel free to share and also see our Facebook page!

WAVE PARTICLE DUALITY OF LIGHT: SUMMARIZED - PART TWO

Continued from WAVE PARTICLE DUALITY OF LIGHT: SUMMARIZED - PART ONE

THE DOUBLE SLIT EXPERIMENT

This is an experiment that proves the wave particle duality of light. It is a simple experiment that involves passing light rays from a single source through a double slit boundary. A screen is placed after the boundary to detect the light rays coming through. The result gotten are;

1.The Light arrives at the screen light a spot and at random(Particle Property)

Light Arrives Randomly
(source: wikipedia.com, 2013)

2.The Result on the screen gives evidence of interference of the light waves (wave-like property)

Light rays during interference.
(source: wikipedia.com)

From the experiment, it can be seen that light is weird.

From all these you can easily point out that light has an identity problem. Who can be the physics doctor to treat this issue?

Help Light, Love Physics.
Any questions or comments? Please do not hesitate to drop them for us or you can also bring it over to our physics page on Facebook.

Please SHARE, DO NOT COPY.
I worked hard to bring this to you. Enjoy!

WAVE PARTICLE DUALITY OF LIGHT: SUMMARISED - PART ONE

Source: commons.wikimedia.org

Light is undoubtedly a type of wave and at the same time, it still exhibits properties that only a particle would exhibit. Now the issue is why?

First lets discuss on what properties makes light a wave.

LIGHT AS A WAVE

Light is a wave, it exhibits all the known properties of waves. From the first to the fifth. Now let us take a quick view through all of these wave-like properties and see the cases where light exhibits them...

1. Refection
probably the most common and explains how we see our images in a mirror.

2. Refraction
the bending of light rays. It explains why a light bends when it changes medium; why a straw appears broken in a clear glass of water and even extends to apparent depth.

3. Interference:
When two identical waves meet in the same medium, they interact with each other in order to strengthen themselves(Constructive) or to destroy(destructive) themselves. This exhibits this too like other waves.

4. Diffraction

Single slit Diffraction of Light
(Source: cronodon.com, 2013. Image was also edited)

Diffraction is the bending of waves when they pass through an opening lower than their wavelength. This is applicable in reading a CD or DVD disc.
Read more on interference and Diffraction here.


5.Polarization
Polarization is the change in the plan of oscillation of light waves. Its occurrence in nature makes the sky appear blue and is used in many other fields.

Light isn't just a wave, it has a family called ELECTROMAGNETIC WAVES it has all their properties. From their common velocity (c= 2.997 x 10^8m/s) to a perfect place in their frequency(400-790THz) and wavelength(380-750nm) spectrum.

Light in the Electromagnetic Spectrum
Source: www.itseducation.asia

LIGHT AS A PARTICLE

Wow, now light is a particle too. It has properties that only particles would exhibit.

1. Light supports the view that its is a stream of particles called PHOTONS.
This was postulated by Albert Einstein. Photons are the smallest unit of radiant energy. They are like small particles that makes up light waves.
-The greater the number of photons, the greater the intensity of light.
-The higher the frequency of oscillation of the photons, the more energy they carry.
This energy is given as E=hf;
where, E = Energy of oscillation of photon
h = Planck's constant (6.63 × 10^-34 m2kg/s)
f = frequency of oscillation.

2.It obeys the law of conservation of momentum, in fact, it can knock off other 'particles' and transfer energy to them.
This is seen in an phenomenon known as the Compton effect.

The Compton Effect

Source: whs.wsd.wednet.edu

This is seen in cases where light rays are used to liberate electrons from the surface of metals (Read Photo Electric Effect). It is noticed that the energy the electrons, leaving the surface of the metal possesses, approximately equal to the energy of the colliding photon. This means that, the laws of conservation of momentum and energy has been obeyed.

Continue to WAVE PARTICLE DUALITY OF LIGHT: SUMMARIZED - PART TWO