photocell

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TO DRAW V-I CHARACTERISTICS OF A PHOTOCELL & TO VERIFY THE INVERSE SQUARE LAW OF RADIATION:

TO DRAW V-I CHARACTERISTICS OF A PHOTOCELL & TO VERIFY THE INVERSE SQUARE LAW OF RADIATION THEORY When a light source is incident on a metallic surface, a light photon transfers the energy to surface electrons causing them to jump the potential barrier Types of barrier jumps Photo emissive jump - Photovoltaic jump Photo conductive jump - Photo conductive jump Photovoltaic Effect : Generation of potential difference between the ends of semiconductor when light of frequency above the threshold frequency of semiconductor material is incident upon its surface.

Slide 2:

Circuit Symbol This is due to charge carrier deposition on incidence of light. Materials used are Germanium (Ge),Silicon (Si) Verification of Inverse Square law

INSTRUMENTS REQUIRED:

INSTRUMENTS REQUIRED *Photocell *Meter rod *Connecting Wires *Light Source Inverse square law of Radiation If L is the luminous intensity of a light source & E is the intensity of illumination at a point distant r from it, then on incidence of this light on photocell then current I measured using a micro-ammeter is proportional to intensity of illumination E is given by WORKING FORMULA

The Physics Beyond…:

The Physics Beyond… Germanium Photocell A minute Germanium layer is deposited over base plate of Aluminium, Steel, Brass. Finally a layer of cadmium or cadmium oxide is used