AH Exp – Wave Phenomena 03B – Determination of wavelength using Young’s slits

Aim – To measure the wavelength of laser light using Young’s slits.

Instructions

▪ View the double slit using the travelling microscope.
▪ Position one of the slits in the centre of the cross hairs in the eyepiece view of the travelling microscope.
▪ Measure the position of the travelling microscope using the Vernier scale.
▪ Move the travelling microscope and measure the separation of the slits.

The screen is initially set at a distance of 2 m from the slits.
▪ View the interference pattern on the graph paper and determine the spacing of the maxima.
▪ Alter the distance from the slit to the screen and again determine the spacing of the maxima.
▪ Draw a graph of the fringe separation (Δx) against the slit to screen distance (D) and use the graph to show the relationship between Δx and D.
▪ Determine a value for the wavelength of the light used.

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