Newton’s Rings Apparatus

A plano-convex lens is placed with its convex surface on the optically plane glass plate so as to enclose a thin film of air of varying thickness between the lens and the plate. Light from an extended monochromatic source is converted into a parallel beam of light by using planoconvex lens of large radius of curvature and 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.

Features:

• Stand alone setup (built in sodium bulb, microscope, HID blast transformer & optics in a single compact body.
• Reflector mounted at 45°(no special adjustment required).
• High quality glass plates (flatness λ/10).
• Heavy rigid body weight 12.6 Kg approx.
• Smooth X & Y movement of reflector assembly.
• Modern compact design required less space in Laboratory.
• Modern user friendly design.

Objectives:

• 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).

Technical Data:

• Linear motion : 10 – 0 -10mm
• Micrometer : Vernier dial 100 div., LC 0.01mm
• Eyepiece : Ramsden 10X
• Objective : 3X
• Spherometer disk(brass) : Types 3 legs, Vertical scale 6 x 6mm(WxT) Micrometer dia. 40mm, Brass lower disc dia. 60mm, Range 10-0-10mm, Least count 0.01mm
• Plano convex lens : Dia. 61.5mm, Glass, Focal length 200mm
• Sodium source : MS housing, 200 x 85mm (LxØ), slit(LxW) 20x16mm
• Sodium bulb : 35W
• Fuse : 2A
• Body : Al casting
• Weight : 12.6 kg approx

Scope of Delivery:

• 1 Newton’s ring apparatus
• 1 Spherometer
• 1 Plano convex lens with plane glass plate
• 1 Plain glass plate pair (50 x 35 x 2mm)
• 1 Plain glass (108 x 70 x 1.2mm)
• 1 Power cord
• 1 Plain glass (75 x 75 x 2mm)
• 1 Sodium bulb

Key Topics:

• Phase relationship
• Coherent light
• Path difference
• Interference.
• Newton’s rings.
• Refractive index.
• Thickness of sheet wavelength.
• Radius of curvature.