An Introduction to Atomic Physics which gives an overall view of atomic physics along with its different aspects. I had done this in my 12th Grade.

2. James Clerk
Maxwell
(1831-1879)
“The aim of exact science is
to reduce the problems of
nature to the determination
of quantities by operations
with numbers”

3. Thermionic emission
Emission of electrons by substances that are
highly heated, the charged particles being
called thermions.
The number of thermions emitted increases
rapidly as the temperature of the substance
rises.

4. The photoelectric effect refers to
the emission, or ejection, of electrons
from the surface of, generally, a
metal in response to incident
light. Energy contained within the
incident light is absorbed by
electrons within the metal, giving the
electrons sufficient energy to be
'knocked' out of, that is, emitted
from, the surface of the metal.

5. It is the process whereby
electrons tunnel through a
barrier in the presence of a
high electric field.

6. Secondary emission
If electrons with energies of 10 to
1000 electron volts strike a metal
surface in a vacuum, their energy is
lost in collisions in a region near the
surface, and most of it is transferred
to other electrons in the metal

7. Real Pictures of
Electron emission

12. Spectrum

15. Spectrum consists of number of Bright lines
against dark background

17. Spectrum consists of series of luminous bands

18. Continuous Absorption
Continuous spectrum with certain range of
wavelengths being cut off
Line Absorption
Spectrum consists of number of dark lines
against bright background
Band Absorption
Continuous spectrum with some dark bands

19. Continuous absorption
Line Absorption
Band absorption

23.  Frequency: > 3 x 1019 Hz
 Wavelength:< 0.1 Ao
 Characters: Ionizing, has momentum
 Discoverer: Paul Villard
 Sources:Sun,stars,Radio active substances

24. moon

26.  Frequency 3 x 1017 - 3 x 1019
Hz
 Wavelength 10 - 0.1 Ao
 Characters: Ionizing
 Discoverer :William Conrad
Roentgen
 Sources: X-ray tube , stars

32.  Frequency 7.5 x 1014 - 3 x 1017 Hz
 Wavelength 4000 - 10 Ao
 Discoverer Johann Wilhelm
Ritter
 Sources sun,
stars, fluorescent tubes

33. UV A -causes aging, wrinkling, and loss of
elasticity of skin
UV B -causes the greatest risk of skin cancer
UV C -very destructive to tissues, however
most is absorbed by the Earth’s atmosphere
before reaching ground level.
UVA: Wavelength: 320-400 nm. Not
absorbed by the ozone layer.
UVB: Wavelength: 290-320 nm. Mostly
absorbed by the ozone layer, but some does
reach the Earth’s surface.
UVC: Wavelength: 100-290 nm. Completely
absorbed by the ozone layer and
atmosphere.

35.  Frequency 4.3 x 1014 - 7.5 x 1014
Hz
 Wavelength 7 x 10-5 - 4 x 10-5 Ao
 Sources sun ,stars, bulbs etc

38.  Frequency 3 x 1012 - 4.3 x 1014Hz
 Wavelength 106 - 7000 Ao
 Discoverer WilliamHerschel
 Sources Globar , Nernst filament hot bodies

39. IR-A: 700 nm–1400 nm (0.7 µm – 1.4 µm)
IR-B: 1400 nm–3000 nm (1.4 µm – 3 µm)
IR-C: 3000 nm–1 mm (3 µm – 1000 µm)

41. Micro Waves
 Frequency 3 x 109 - 3 x 1012 Hz
 Wavelength 109 - 106 Ao
 Characters Heat objects
 Discoverer John Randall and H.A. Boot

45. Radio Waves
 Frequency: < 3 x 109 Hz
 Wavelength :>109 Ao
 Discoverer: Heinrich Rudolf Hertz

48. CRYOGENIC ELECTRON EMISSION
 At very cold temperatures, in the absence of light, a
photomultiplier will spontaneously emit single
electrons. The phenomenon, which is called
"cryogenic electron emission," was first observed
nearly 50 years ago. Although scientists know of a
few causes for electron emission without light (also
called the dark rate) - including heat, an electric
field, and ionizing radiation - none of these can
account for cryogenic emission. Usually, physicists
consider these dark electron events undesirable,
since the purpose of a photomultiplier is to detect
photons by producing respective electrons as a
result of the photoelectric effect.

49.  The dark rate decreases as
temperature decreases
Below about 220 K (-53° C), the
dark rate levels off
With further cooling, it begins to
rise, and continues to increase at
least down to 4 K (-269° C)

51. We thank our respected Santosh Sir for
giving us this wonderful opportunity!!!!!!!!
By,
Aravind .M &
Sujith Athri H.S.
Animations By
Karan U
Shinde