This document discusses the photoelectric effect and its applications. It begins by introducing the presenters and their student IDs. It then provides definitions and characteristics of the photoelectric effect, including Einstein's explanation that light is made up of discrete quanta of energy called photons. The document discusses the experimental setup used to demonstrate the photoelectric effect and describes photoelectric cells, their construction and working. It outlines applications of the photoelectric effect such as night vision devices, cameras, solar cells, burglar alarms, and light sensors.

1. TO OUR PRESENTATION
1

2. PRESENTATION TOPIC
2

3. PRESENTED By
FAISAL
191003045
SAJIB
191003054
NAYEM
191003058
MIRON
191003089
ASIF
191003072
KOWSHIK
191003078
BAYZID
191003044
SHARIAR
191003049
BATCH
191(B)
3
NUSRAT
191003060

4.  When a beam of light of
sufficiently high frequency
onto a clean metal surface
then the light will cause
electrons to leave the
surface.
 Definition : the
phenomenon of emission
of electrons by the metals
when they are exposed to
light of suitable frequency
is called as the photo
electric effect and
emitted electrons is called
as photoelectrons.
Photo electric effect
4

5. • A photon is absorbed by an electron in a metal surface causing an electron to
be emitted.
(E) Energy of photon = h*f
Energy is conserved, “f” is the frequency , “h” planks constant
h=6.626 × 10−34 js
• Only electrons with energy above the work function energy will be emitted.
• Only light with a frequency greater than the threshold frequency will cause
emission
• Energy=work function + Max KE of electron.
E=hν−Φ or K.E=hν−Φ
The Photoelectric Effect Equation
5

6. 6
The Photoelectric Effect Equation

7.  Threshold frequency is different for different material.
 Photoelectric current is directly proportional to
intensity of light.
The K.E. of photoelectrons is directly proportional to
frequency of light.
 Stopping potential is directly proportional to
frequency.
 The process is instantaneous.
Characteristic of photoelectric effect
7

8. 8
 In 1905, Einstein proposed that electromagnetic
radiation or light is made up of photons. Thus the
photon is the elementary element of light or light is
made up of photons.
 Einstein show that- light energy is not emitted
continuously but it is emitted by individual amount of
energy called as quantum of energy.
PHOTON (QUANTUM OF LIGHT)

9. 9
 According to Einstein, each photon of a light
wave of frequency has the energy E is given by,
E= hν ………1
 Where
E= energy of photon(joule)
h= planks constant-6.626 x 10-34 J.s
ν= frequency of photon(Hz)
Energy of photon

10. 10
 A photon does not have any mass.
 A photon does not have any charge and are not
deflected in electric field or magnetic field.
 All the quantum numbers are zero for a photon
 In empty space, the photon moves at speed of
light.
 In the interaction of radiation with matter, radiation
behaves as if it is made up of particles called photons.
 The energy and momentum of a photon are related
As follows
E= p.c where p- magnitude of momentum and
c is the speed of light.
 Photon is called as a virtual particles.
Properties of photon

11. 11
. The filter passes light of certain
wavelengths from the lamp at left. The light
strikes the curved electrode, and electrons
are emitted. The adjustable voltage can be
increased until the current stops flowing.
This "stopping voltage" is a function only of
the electrode material and the frequency of
the incident light, and is not affected by the
intensity of the light
Schematic of experimental apparatus to
demonstrate the photoelectric effect

12. 12
 Principle : a photoelectric
cell is a device which
converts the light energy
into an electrical energy.
 Construction : it consists
of an evacuated glass
tube. Inside this tube
photosensitive metal
plate which is called
emitter and a wire loop
A which is acts as
collector.
Photo electric cell

13. 13
 A high tension battery and micro ammeter (UA) are connected to
plate C and loop A as shown in fig.
 Working : When the light of suitable frequency is incident on the
emitter C, it start emitted the photoelectrons are attracted
towards the collector A.
Working of photoelectric cell

14. 14
 Construction: 1)the Hertz experimental
set up used for studying the photoelectric
effect is shown in above fig.
 2) the set up consist of an evacuated
glass tube that has a photosensitive metal
plate C and another metal plate A as
shown.
 A monochromatic light source emerging
from the source S of sufficiently short
wavelength enters the glass window W
and fall on photosensitive plate C, is called
emitter.
Photoelectric effect

15. 15
 Working: when a beam of light fall on photosensitive
metal plate c which is called emitter.
 The plate c emits photoelectrons due to photoelectric
effect. The photo electrons emitted by plate c will be
attracted towards the positive plate A. these electron
flows in the eternal ckt to cause an electric current in
the ckt.
 Such a current is known as the photoelectric current
and measured by the micrometer connected in the ckts.
Photoelectric effect

16. APPLICATIONS & USES
16
Night vision devices
Photons hitting a thin film of
alkali metal
or semiconductor material
such as gallium arsenide in
an image intensifier tube
cause the ejection of
photoelectrons due to the
photoelectric effect

17. CAMERA
17

18. 18
Solar cell
Photoelectric effect also work for solar cell

19. 19
Burglar Alarm
Photoelectric cell are also used for burglar alarm

20. 20
Light sensor
Light sensor work by photoelectric effect

21. 21
1. Photoelectric Effect - Proved to us
that light sometimes can act like a
particle
2. What's the Photoelectric Effect?
- When you shine light on certain metals they give off
photoelectrons
3.What’s the function of photoelectric effect?
- photons working in the theoretical prove
4.Uses of photoelectric effect - Shows different applications and real life uses.
SUMMARY

22. 22