Title: Special theory of Relativity-ppt-N.V.V.S.Murty
1Power 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
2 Topic
Special Theory Of Relativity
3Special 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."
4Galilean 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
5 Lorentz transformations
- Hendrik Antoon Lorentz
- Nationality Netherlands
- (1853 -1928)
6Values 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
7Plot results
?
1 ?1 v2/c2
g
Never-never land
x
x
x
x
x
vc
8- 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)
9Michelson-Morley
Morley (1838-1923)
No aether wind detected 1907 Nobel Prize
10Michelson Morley Expt
11Michelson Morley Expt
12Derivation 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.
13(No Transcript)
14Michelson Interferometer
15Length contraction
v
L0
timet L0 vt
Shorter!
man on rocket
Time t0 t/g Length vt0
vt/g
L0/g
16Moving 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
17Length contraction (Lorentz-Fitzgerald
contraction)
George Francis FitzGerald
(1851-1901) Born Ireland
18Moving clocks run slower
v
t0
t t0
1 ?1 v2/c2
t
t g t0
g gt1 ? t gt t0
19Relativistic 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
20"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.
21summary
- Moving clocks run slow
- Moving objects appear shorter
- Moving objects mass increases
By a factor of g
22If there are any suggestionsor commentsfeel
free to write to my mail in the first slide
Thank you all