Higher Physics Lab Soild State Physics



Exp-1 To study the current vs voltage characteristics of CdS photo-resistor at constant irradiance.
Exp-2 To measure the photo-current as a function of the irradiance at constant voltage.

  • Multipurpose power supply.
  • Electrical safety tested.
  • Adjustable slit self centering.
  • Marked analyzer & polarizer for angle measurement.
  • Photo resistor.
  • Photo current.
  • Irradiance.

Principle and Working:
Absorption of light increases electrical conductivity in a solid. In case of cadmium sulphide (CdS) photoresistor, when it is exposed to light the transition of activator electrons into the conduction band and charge exchange of traps with holes being created in the valence band causing enhancement of conductivity.
In the present setup, photo current is studied as a function of the voltage applied to the photo resistor at a constant irradiance. The angle of polarization is changed by polarizer filter.


Cat. No. Item Name Qty.
SL804 Photoresistor in holder (CdS) 1
SE080 Power supply 12V AC/DC 5 Amp. 1
SL803 Lamp housing 1
SL754 Convex lens in holder 1
SL801 Polarizer/Analyzer (pair) 1
SL214 Optical bench 1
SL802 Adjustable slit self centering 1
SE079 Reg. power supply, 0-16V DC, 5A 1
SE067 Digital multimeter 1
SN203 Flexible plug lead, 50 cm (Red) 2
SN201 Flexible plug lead, 1m (Black) 1
SL216 Shaddle 1
SL436 Transversal saddle 1

Solid State Physics Experiments