Theory of Relativity Assignment Help




Special relativity (SR, also known as the special theory of relativity or STR) is the physical theory of measurement in inertial frames of reference proposed in 1905 by Albert Einstein

mass–energy equivalence formula E = mc^2, where c is the speed of light in a vacuum.

Albert theory of relativity

Albert Einstein was one of the most, famous physicists in the world have we ever known. Albert Einstein’s one of the greatest achievements was his Theory of Relativity, which paves the way for how science currently views time, space, energy, and gravity. Since, Einstein was an advanced thinking person in the direction of his studies as well as his works he put the standards for the control of scientific energy and space explorations currently being studied in the field of astrophysics. This makes us to think about many things, including what would happen to our view of the world if we could travel very fast.

Approach to Albert Einstein Theory of Relativity

The Albert Einstein’s theory of relativity, or just relativity, encloses within the two theories of Albert Einstein: they are The Theory of special relativity and the Theory of general relativity. On the other hand, the word "relativity" is sometimes used in reference to Galilean invariance.

The “Theory of relativity" was proposed by Max Planck in the year 1908 to highlight how the theory of special reactivity and the theory of general reactivity use the principle of relativity.

Special Relativity

The theory of Special relativity could explain the structure of space-time. It was included in the paper "On the Electrodynamics of Moving Bodies" (for the contributions of many other physicists see History of special relativity) by Albert Einstein in 1905. This theory is based on objects.

According to the Albert Einstein’s theory of relativity, the defining feature of special relativity is the alternate of the Galilean transformations.

Two postulates which are opposing in classical mechanics:

  • According to this theory the laws of physics are found to be the same for all the observer in uniform motion relative to one another (principle of relativity),

  • In a vacuum the speed of the light is found to be the same for all observers, in spite of their relative motion.

  • The resulting theory agree with experiment better than classical mechanics, e.g. in the Michelson-Morley experiment that supports postulate 2, it also has many other subsequent consequences. Some of these are:

  • Relativity of simultaneity: when any two events occur, which may be simultaneous for one observer, possibly will not be simultaneous for another observer if the observers are in relative motion.

  • Length contraction: The directions of the object are found to be much shortened with respect to the movement of the observer.

  • Mass-energy equivalence: According to the energy equation E = mc2, energy and mass are found to be equivalent and transferrable.

  • Maximum speed is finite: The light can travel much faster than the any other Albert Theory of Relativity

The Albert Einstein Theory on General Relativity

General relativity explains about the theory of gravitation put forth by Einstein between the years 1907–1915. The development of this theory explains about the equivalence principle, under which the accelerated motion and gravitational field are physically identical. This theory shows incompatibility with classical mechanics and special relativity because in those theories inertial moving objects cannot accelerate with respect to each other, but objects in free fall do so. To overcome this difficulty Einstein first coined that space-time is curved. In 1915, he put forth the Einstein field equations which relate the curvature of spacetime with it.

Thus, technically speaking general relativity is a metric theory of gravitation whose essential feature is its use of the Einstein field equations. The solution for the field equations is metric tensors which define the topology of the space-time and inertial movements of an object.

Introduction to special theory of relativity:

In physics, special relativity is a fundamental theory about space and time, developed by Albert Einstein in 1905 as a modification of Galilean Relativity. It was able to explain some pressing theoretical and experimental issues in the physics of the late 19th century involving electro magnetic waves, such as the failure of the Michelson - Morley experiment in 1887, which aimed to measure differences in the relative speed of light due to the motion of Earth through the hypothetical luminiferous aether, which was then considered to be the medium of propagation of electromagnetic waves such as light.

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Postulates of Special Theory of Relativity:

1.The laws of physics are same for all the inertial frames of reference.
2.The velocity of light in free space is constant in all the frames of reference. According to this second postulate of special theory of relativity the velocity of light in vacuum is constant whether the observer measures it moving in the same direction or in its opposite direction. Its value in vacuum is approximately 2.99797 * 10 ^ 8 m/s.

In the light of special theory of relativity the newtonian mechanics becomes invalid. Newtonian mechanics is valid when the velocity of the moving objects are within some range. But nowadays, the velocity of few particles like electron beam, are comparable with the velocity of light. In these situations Newton's laws of motion are invalid. So developed Quantum Mechanics.

Absolute value and simultaneity are possible in classical mechanics which obeys Newton's laws of motion. But after the special theory of relativity even simultaneity itself is relative. The relative motion between the object and observer plays important role.

Using special theory of relativity we can see the relativistic change of the following:

t = \frac{T}{\sqrt{1 - \frac{v^2}{c^2}}} \,

where t is the time interval between two events when the relative velocity between the observer and the object is v and T is the time interval between the same events when the relative motion is zero and  c is velocity of light. This is clear that time interval increases which is known as "Time Dilation".

In the same we can show the length contraction or Lorentz - Fitzgerald contraction using the following expression,

x = X \sqrt{1 - \frac{v^2}{c^2}} \,

where x is the length when the velocity is v and X is the length of the object when it is at rest.

According to Special Theory of relativity every thing is relative when they are in high speed, that is comparable to the speed of light

Applications of Special Theory of Relativity:

There is a common perception that relativistic physics is not needed for practical purposes or in everyday life. This is not true. Without relativistic effects, gold would look silvery, rather than yellow. Many technologies are critically dependent on relativistic physics:

  • Cathode Ray Tube,
  • Particle Acceleratiors,
  • Global positioning System (GPS )
  • Einstein showed that mass is simply another form of energy. The energy equivalent of rest mass m is mc2. This equivalence implies that mass should be interconvertible with other forms of energy. This is the basic principle behind atom bombs and production of energy in nuclear reactors and stars (like the Sun).

Important result from the special theory of relativity:

No object can travel with the velocity of light ( if it happens so, then the length of the object at the speed of light will be zero and its mass will be infinity). This is an important finding using this Special Theory of Relativity

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