Published on: **Mar 3, 2016**

Source: www.slideshare.net

- 1. EINSTEIN’S THEORIES OF RELATIVITY
- 4. <ul><li>It was believed to occupy all cosmos. </li></ul><ul><li>It is undetectable by ordinary means. </li></ul><ul><li>It was supposed to permeate all matter and space. </li></ul><ul><li>It was supposedly a medium to act as a carrier of waves, including light. </li></ul>
- 5. (c)RiA
- 6. <ul><li>The results were negative, even after repeating it six years later. </li></ul>
- 7. <ul><li>The ether was not stationary but was dragged along with the earth. </li></ul><ul><li>The earth was fixed in the ether and everything else in the universe moved with respect to the earth and the ether. </li></ul><ul><li>The velocity of light was always at constant with respect to the source which emitted it. </li></ul><ul><li>Ether did not exist at all. </li></ul>
- 9. <ul><li>This postulate concerns the constancy of the speed of light to all observers . </li></ul><ul><li>All measurements, whether stationary or moving observers relative to a moving or stationary source always give the same value for the speed of light, c=3x10 m/s . </li></ul><ul><li>This postulated is supported by the results of the Michelson-Morley Experiments . </li></ul>8
- 10. <ul><li>This postulate concerns “relativeness” of reference frames (principle of relativity). </li></ul><ul><li>It follows directly from the absence of a universal frame of reference. </li></ul><ul><li>A place moving with constant velocity are the same as those in a stationary place. </li></ul>
- 11. <ul><li>Uniqueness of light –the speed of light is the same for all observers whether moving or not. The speed of light is an invariant. </li></ul><ul><li>Irrelevance of Velocity –there is no absolute reference frame. All frames are equivalent with respect to the laws of physics. </li></ul>
- 13. <ul><li>The length of an object is maximum when measured in a frame which is at rest; the length is minimum when measured in a moving reference frame. </li></ul><ul><li>L = L √1 – v / c </li></ul>0 _______ 2 2
- 14. <ul><li>Time is affected by relative motion. </li></ul><ul><li>Time runs slower in a moving reference frame than in a stationary frame. </li></ul><ul><li>t’ = t </li></ul><ul><li>√ 1 – v / c </li></ul>_______ 2 2 _______
- 15. <ul><li>Classical physics regard mass as constant, but mass according to relativity is also dependent on motion. Therefore, the mass of a body changes as the body is set into motion. </li></ul><ul><li>m = m </li></ul><ul><li>√ 1 – v / c </li></ul><ul><li>*Nothing can exceed the speed of light; it is the limit to which moving objects can approach. </li></ul>0 _______ _______ 2 2
- 16. <ul><li>Mass is a form of energy. E = mc shows that 1kg of mass = 9 X 10 J </li></ul><ul><li>Significance of the Special Theory of Relativity: </li></ul><ul><li>1.) Effect of Newtonian Mechanics </li></ul><ul><li>2.) The practical use of relativity is in atomic and nuclear physics. </li></ul><ul><li>3.) Philosophical impact on the course of physical theory. </li></ul><ul><li>4.) The idea of ether had to be discarded. </li></ul>2 16
- 17. <ul><li>Experimental results that support the Special theory of Relativity: </li></ul><ul><li>1.) Radioactive Particle Experiments </li></ul><ul><li>2.) Elementary Particle Experiments </li></ul><ul><li>3.) The Cockroft and Walton Experiment </li></ul>
- 19. <ul><li>Einstein published the General Theory of Relativity which was an attempt to account for the properties of motion in accelerated and noninertial frames of reference. </li></ul><ul><li>The basis of this theory is the Principle of Equivalence : </li></ul><ul><li>A homogeneous gravitational field is completely equivalent to a uniformly accelerated reference frame. </li></ul>
- 21. <ul><li>Space and are dynamic quantities. </li></ul><ul><li>Space-time is flat in free space. Space-time is curved or warped near gravitational fields. </li></ul><ul><li>Objects that follow the shortest path between two points in a curved space (Geodesics). </li></ul><ul><li>Gravity is a consequence of the fact that space-time is curved. </li></ul><ul><li>Light rays also follow geodesics. Light is bent by gravitational fields. </li></ul>
- 22. <ul><li>The principle of equivalence is the deflection of a light beam in a gravitational field. </li></ul><ul><li>Light will accelerate (hence, it is deflected) in a gravitational field. </li></ul>