Special theory of Relativity-ppt-N.V.V.S.Murty

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Power point presentationBy

• NEMANI.V.V.S.N.MURTY, M.Sc.,
• Lecturer in Physics
• S.K.B.R.College , AMALAPURAM
• E.G.Dt , Andhra Pradesh
• E-mail vvsmnemani_at_gmail.com

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Topic
Special Theory Of Relativity
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Special Theory of Relativity was developed by
Albert Einstein in 1905
Albert Einstein (1879-1955 ) Born Germany
The Postulates of the Special Theory of Relativity

• The laws of physics are the same in all
  inertial frames."
• The speed of light is constant in all frames."

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Galilean Transformations
Galileo Galilei (1564 -1642 ) Born Italy

• Given two frames, one moving at constant velocity
  with respect to the other, how do we transform
  the coordinates?
• The traditional answer would have been

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Lorentz transformations

• Hendrik Antoon Lorentz
• Nationality Netherlands
• (1853 -1928)

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Values of g - chart
v g 1/?(1-v2/c2)
0.01 c 1.00005
0.1 c 1.005
0.5c 1.15
0.6c 1.25
0.8c 1.67
0.9c 2.29
0.99c 7.07
1.00c ?
Larger than c Imaginary number
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Plot results
?
1 ?1 v2/c2
g
Never-never land
x
x
x
x
x
vc
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• Lorentz and Fitzgerald never denied the existence
  of ether. They postulated an independent effect
  ("contraction") that masked its visible
  consequences.

• However Poincare, in 1900, asked the question
• "Does the ether really exist?"

Residence France
Nationality French
Jules Henri Poincaré (18541912)
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Michelson-Morley
Morley (1838-1923)
No aether wind detected 1907 Nobel Prize
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Michelson Morley Expt
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Michelson Morley Expt
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Derivation of expression for fringe shift

• The time taken by the light ray to travel the
  longitudinal path t1
• The time taken by the light ray to travel the
  Transverse path t2
• Time difference t1- t2
• If the apparatus is rotated through 900 , then it
  will become t2- t1
• Time interval between original position and after
  rotated through 900 2(t1- t2)
• Fringe shift
• Where v 3?104 m/s, c 3?108 m/s, d 11 m, and
• ? 600 nm 600?10-9 m
• Hence 0.4 of fringe.
• The apparatus was able to measure a fringe shift
  of 0.01 of fringe. But Michelson and Morley could
  not observe any fringe shift experimentally. This
  is the negative or null result . Hence they
  concluded that there is no ether medium.

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Michelson Interferometer
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Length contraction
v
L0
timet L0 vt
Shorter!
man on rocket
Time t0 t/g Length vt0
vt/g
L0/g
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Moving objects appear shorter
Length measured when object is at rest
L L0/g
g gt1 ? L lt L0
V0.1c
V0.86c
V0.99c
V0.9999c
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Length contraction (Lorentz-Fitzgerald
contraction)
George Francis FitzGerald
(1851-1901) Born Ireland
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Moving clocks run slower
v
t0
t t0
1 ?1 v2/c2
t
t g t0
g gt1 ? t gt t0
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Relativistic mass increase
m0 mass of an object when it is at rest
? rest mass
mass of a moving object increases
g
as v?c, m??
m g m0
as an object moves faster, it gets harder
harder to accelerate
by the g factor
vc
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"The mass of a body is a measure of its energy
content"
Albert Einstein"
A theory can be proved by experiment but no
path leads from experiment to the birth of a
theory.
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summary

• Moving clocks run slow
• Moving objects appear shorter
• Moving objects mass increases

By a factor of g
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If there are any suggestionsor commentsfeel
free to write to my mail in the first slide
Thank you all