Photoelectric Effect
Chapter Name : Dual Nature Of Radiation And Matter |
Sub Topic Code : 101_12_11_03_02 |
Topic Name : Photoelectric Effect |
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Sub Topic Name : Hallwachs' And Lenard's Observations |
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Introduction
In the photoelectric effect, electrons are emitted from matter (metals and non-metallic solids, liquids or gases) as a consequence of their absorption of energy from electromagnetic radiation of very short wavelength, such as ultraviolet radiations.
Pre-Requisites:
Photoelectric effect
Activity:
Video camera and digital cameras work by the principle of photo electric effect.
Real Life Question:
What is electron emission ?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Photoelectric effect | The photoelectric effect refers to the emission, or ejection, of electrons from the surface of, generally, a metal in response to the incident light. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Video camera | Video camera tubes in the early days of television used the photoelectric effect. |
Real life uses :
Digital cameras. A photon hits the sensor, liberating an electron which is then measured by the camera.
Places to visit :
Studios
Practical examples around us
| Examples | Explainations |
|---|---|
| Garden | Various plants absorb nutrients and water. |
What you learn in Theory:
The photoelectric effect refers to the emission, or ejection, of electrons from the surface of, generally, a metal in response to the incident light.
What you learn in Practice:
It was found that certain metals like zinc, cadmium, magnesium, etc. responded only to ultraviolet light having short wavelength, to cause electron emission from the surface.