HO-ED-INT-01 Newton's Rings Apparatus
Couldn't load pickup availability
Newton's Rings Apparatus
In this apparatus, light from a sodium lamp falls on the glass plate, inclined at 45 degree to the horizontal, get reflected, and then falls normally on the convex lens placed over the glass plate. A system of bright and dark concentric circular rings are observed through a microscope, arranged vertically above the glass plate. The microscope is properly focused so that alternate bright and dark concentric circular rings are observed more clearly. Measurements are taken from a micrometer driven traveling microscope, which is integrated with this apparatus.
Experiment:
To determine the wavelength of Sodium light and LEDs ( Red, Blue, Green, Yellow ).
Let Dm and Dm+k be the diameters of the mth and (m+k)th dark ring respectively. Then,
D2m = 4 mRλ
D2m+k = 4 (m+k) Rλ
D2m+k - D2m = 4 kRλ
λ = [D2m+k - D2m] / 4kR
D2m = 4 mRλ
where λ is the wavelength used and R is the radius of curvature of the lens.
To find the refractive index of liquid.
Refractive index of liquid,
( n = mλR / r^2 )
where, m order of the fringe, R Radius of curvature of the lens
λ wave length of light, r radius of the ring
To find the diameter of thin wire or thickness of a thin strip of paper using air wedge method.
The diameter or thickness of the wire,
d = lλ / 2β
λ is the wavelength of the light
β is the bandwidth
l is the diameter of the wire or thickness of a thin strip of paper from the line of contact of the two plates of the air wedge.
Specifications:
| Travelling Microscope | |
| Magnification | 10 x |
| Micrometer travel | 25 mm |
| Least count | 0.01 mm |
Features:
| Sodium vapor lamp and spectral LED's are used as light sources |
| Traveling microscope with precision micrometer is used for accurate measurements |
| The optics used in this device are of research quality |
| All materials used in this setup are of laboratory grade and are corrosion resistant |
Drawings:
Scope of Supply: