+2 votes
in JEE by kratos

Your teacher gives you a slide with two closely spaced slits on it. She also gives you a laser with a wavelength λ = 632 nm. The laboratory task that you are assigned asks you to determine the spacing between the slits. These slits are so close together that you cannot measure their spacing with a typical measuring device.

(a) From the list below, select the additional equipment you will need to do your experiment by checking the line next to each item.

Meterstick Ruler Tape measure Light-intensity meter Large screen Paper Slide holder Stopwatch

(b) Draw a labeled diagram of the experimental setup that you would use. On the diagram, use symbols to identify carefully what measurements you will need to make.

(c) On the axes below, sketch a graph of intensity versus position that would be produced by your setup, assuming that the slits are very narrow compared to their separation.

(d) Outline the procedure that you would use to make the needed measurements, including how you would use each piece of the additional equipment you checked in (a).

(e) Using equations, show explicitly how you would use your measurements to calculate the slit spacing.

1 Answer

+1 vote
by kratos
 
Best answer

(a) Meterstick, Tape measure, Large Screen

(b)

(c)

(d) Set up the laser to shine on the slide, and set the screen far away on the other side of the slide. Measure the distance L from the slide to the screen with the tape measure. Use the ruler to measure the distance x between adjacent maxima.

(e) With the values obtained above, plug into m λ = d x / L, with m = 1 for the first spot and other variables as defined above and the known λ of the laser used, solve for d. Assuming angle θ is small. It not, determine theta and use m λ = d sin θ

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