Newton’s Rings Experiment

Item Code: SK029

Working and Principle :

The light from monochromatic source is made to fall on an optically plane glass plate inclined at an angle of 45° to the vertical, where it gets reflected on to the plano-convex lens. The wavelength of monochromatic light source is determined from the radii of the interference rings.




  • Modular approach.
  • Economy model.
  • Moveable reflector arrangement.
  • Fine X-axis movement of microscope.
  • Microscope can be used vertically and horizontally.
  • High quality glass plates (flatness λ/10).
  • Sodium source can be used in vertical & horizontal positions.

  • To determine the wavelength of sodium light.
  • To determine the refractive index of a liquid by using Newton’s rings apparatus.
  • To find the radius of curvature of planoconvex lens using spherometer.
  • To find the thickness of a thin sheet of paper (air wedge experiment).
  • Type : Bridge type microscope
  • Main scale : Range 0 -170mm, 1 MSD 0.5mm
  • Vernier LC : 0.01mm
  • Magnifier : FL 50mm, dia. 25mm
  • Eyepiece : Ramsden 10X
  • Objective : 3X
  • Spherometer disk(brass) : 3 legs, Vertical scale 6 x 6mm(WxT Micrometer 40mm, Brass disc dia. 60mm, Range 10-0-10mm, Least count 0.01mm
  • Plano convex : Dia. 61.5mm, Glass, FL 200mm
  • Lens holder : 80 x 30mm
  • Sodium source : MS housing, 200 x 85mm (LxØ), slit (LxW) 20x16mm
  • Sodium bulb : 35W
  • Reflector ass. : PVC, 105 x 100 x 110mm
  • Fuse : 2A
  • 1 Reflector assembly
  • 1 Sodium light source
  • 1 Bridge type microscope
  • 1 Wooden block
  • 1 Spherometer double disc with glass plate
  • 1 Plano convex lens with plane glass plate
  • 1 Lens arrangement
  • 1 Plain glass plate pair (50 x 35 x 2mm)
  • 1 Power cord
  • 1 Plain glass (75 x 75 x 2mm)
  • 1 Plain glass (122 x 89 x 1.8mm)