Kerr Effect

Item Code: SK019

Working and Principle :

Certain materials under the influence of strong electric field become doubly refractive. The effect known as Kerr effect can be observed in this experiment with nitrobenzene solution.

In the present setup, a small glass container mounted with plate capacitor is filled with liquid. The container is kept between two filters placed at 90°. There will be dark field of view on screen initially but after applying electric field, the field of view brightens, because the light beam becomes elliptically polarised when passed through the birefringent liquid.




  • All electrical connections are made using 4mm safety sockets and plugs
  • Saddle can hold rod from 8 to 15mm.
  • Heavy, rigid and stable Triangular Optical bench (made of Al extrusion).
  • Height and level adjustment screws (made of SS)
  • Analyser/Polayser with 0 ± 90° graduation.
  • Electrode with 4mm safety socket (for 6 kV).
  • High voltage DC power supply with thermal safety switch.

Learning Objectives/experiments

  • To demonstrate the kerr effect in nitrobenzene solution.
  • To observe brightness on detector depending on voltage applied.
  • To determine half wave voltage for blue light.
  • To determine kerr constant.
  • Halogen lamp : 12 V, 35 W, horizontal filament
  • Kerr Cell : Glass, Dimensions 50x50x20 mm
  • Electrode : MS material, 1mm gap
  • Optical bench : Al exclusion, L=1 mtr., Triangular shape with end stop, 4 point levelling (SS screw)
  • Transversal slider : 25 – 0 – 25mm, LC 0.01mm
  • Polarizer : Angle (0 + 90°), LC 1°, Aperture 21mm, Frame 130mm, Rod 10 mm
  • Colour filter : Blue 465 – 475 nm, Dia. 25-30mm
  • Fixed slider : Al Extrusion, Base width 50mm, H 115mm
  • Power supply : Output 2,3,4,5,6,8,10,12,14V, D C i s f u l l wave rectified, unsmoothed & unregulated, thermal reset switch
  • HV Power supply : 0-6 KV DC (50μA & 2mA), 6.3V AC/ 2Amp Display 3 ½ digit LED
  • 1 Kerr cell with electrode
  • 2 Polarizer / Analyzer
  • 1 Halogen light source
  • 1 Object screen
  • 1 High voltage power supply
  • 1 Power supply
  • 1 Prism table
  • 1 Optical bench triangular
  • 1 Convex lens in holder
  • 1 Blue filters
  • 1 Pair of flexible plug lead,50cm (Red & Black)
  • 1 Pair of flexible plug lead,100cm (Yellow)
  • 1 Pair of flexible plug lead,100cm (Red & Black)
  • 1 Transversal slider
  • 1 Silicon detector
  • 1 Digital Multi meter
  • 2 Power cord
  • 4 Fixed slider
  • 1 Fixed slider (large)