Einstein theory

1. Nainesh Kansagara
Lab – 02

2. 2
 Born in Germany on 14 March, 1879
 In 1901, started job in patent office as a
clerk
 Age of 26, In 1905, submitted a Theory of
Relativity to German journal ‘’Annalen der
physic’’.
 In 1915, his General theory of relativity was
published
 Einstein got the Nobel Prize in 1921 For his
work on photoelectric effect and theoretical
physics
Who was Albert Einstein?

3. 3
The Special Theory of Relativity: The Basic
 Prior to Einstein, everyone agreed the distance between events depends
upon the observer, but not on the time.
 Special theory of relativity said, if speed increases, time slowdowns
Because universe has not only three dimension, but fourth one is time
 Time itself cannot exist in the absence of matter and space
 Speed of light is absolute, rest every thing is relative

4. 4
The Special Theory of Relativity: The Basic
What is relative? ....
Speed of person is 102 m/sec
Speed of train is relative.
for observer

5. 5
The Special Theory of Relativity: The Basic
The Special Theory of Relativity
Equivalence of Mass
and Energy
Moving object appear s shorter
Moving clock runs slow

6. 6
Moving clock runs slow
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To = time on Earth clock (observer)
d2 + (VTo)2 = (CTo)2
(CTs)2 + (VTo)2 = (CTo)2
(CTs)2 = (CTo)2 - (VTo)2
(CTs)2 = (C - V)2 To2 Ts = time on moving clock
To = Ts g
To = Ts
1
 1 – V2/C2
d
VTo
CTo
Mirror
How is To related to Ts?
Source of light
d= CTs
To2 = Ts2 C2
C2 – V2
this is called g
Time depends on state of
motion of the observer !!

7. Here, T = time of space shuttle clock
T0 = time of Earth (observer time)
V = speed of space shuttle
C = speed of light (3X108 m/sec)
Suppose,
One space shuttle speed having 2,94,000 km/sec,
can also say this speed is around 98% speed of
light. So, V/C = 0.98
1 – (V/C)2
T0
T =
1 – (V/C)2
T0
T =
1 – 0.9604
1
T =
1 – (0.98)2
1
T =
T = 5
Moving clock runs slow
Time slowdowns five times means if 25 year passed on earth, space
shuttle feel 5 years only…

8. Moving objects appear shorter
Consider two “markers” in space.
Suppose spacecraft flies between two markers at velocity V
Compare what would be seen by observer and an astronaut ?
Observer at rest says: Distance Lo= V  to
Astronaut says: Distance is LS= V  ts
We know from earlier that
Therefore, LS = V  ts
= V  ts (to / to)
= Lo /g
Ls = L0 1 – (V/C)2
1
1 – v2/c2g =
ts = to g Lorentz factor, g

9. Moving objects appear shorter
Suppose, one train is travelling with speed of 100 m/sec, we do not have to measure
the length of train by measure tap and we want to know the length of train ?
How can we measure it ?
Length = required time (clock of train) X speed
= 5 X 100
= 500 meter length of train
But speed of train is near about 87% speed
of light then?
It will be a half because time will be half
L = contracts space
L0 = normal distance
V = train speed
C = light speed
L = 500 1 – (0.87)2
L = L0 1 – (V/C)2
L = 500 1 – 0.7569
L = 250 meter

10. Moving objects appear shorter
Muon Lifetime:
Muon has (average) lifetime is 2.2 X 10-6 sec.
Around 10 km up, when cosmic rays enter into atmosphere of earth it forms muon
particle
How are we able to observe them on the earth?
and speed of that particle is 99.90%
of speed of light
L = 10 1 – (0.999)2
L = L0 1 – (V/C)2
L = 0.447 km
Muon particle feels only
0.447 km distance
instead of 10 km, due to
space contracts.

11. Equivalence of Mass and Energy
 Einstein thought that a substance like radium always release energy via
radiation. In spite of that, apparently quantity of radium is not decreased.
Why???...
 Here energy is generated. That is not possible. So it is possible that source
of energy is only a substance
 So, there is no difference between energy and substance.
E0 = mc2
 Even a particle has no velocity and therefore no kinetic energy, it still
has energy by virtue of its mass.

12. Equivalence of Mass and Energy: Example
The chain reaction of hydrogen to helium
Two H2 convert to He
M wt of H is 1.00794 X 4 = 4.03176
and He M wt is 4.00260 (diff- 0.02916)
It is 0.7% wt loss
It means 1 kg hydrogen convert to 0.993 kg He and remaining 0.007 kg mass
convert to energy but how much ???
E = Mc2
E = energy in J, m = Mass in kg,
c = velocity of light in meter (3X108 m/sec)
E = 0.007 X 9 X 1016
= 6.3 X 1014 J
What if speed increases than
the speed of light?
As per formula, that is not
possible and excess energy
of speed converts into mass.
Logically we can say, 1000 watt bulb could be
continuously on up to around 20,000 year.

13. Lesson from work of Einstein
 The true lessons to be derived from Einstein’s life and work are
perhaps the following:
 Think clearly
 Follow your intuition
 Do not be discouraged by others
 Work hard
 Learn all you can – but use only what you need
 There are also lessons to be learned from Einstein’s critics:
 Criticism if right will be forgotten, if wrong then remembered
 Each new idea looks jarring. That neither makes it right nor wrong.
 Progress usually comes from the least expected direction. But for this
reason, we cannot guess where to expect it!

14. Thank You
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