Chapter 33: Wave Optics

Light of $630\mathrm{nm}$wavelength illuminates two slits that are$0.25\mathrm{mm}$apart. FIGURE $\mathrm{EX}33.5$shows the intensity pattern seen on a screen behind the slits. What is the distance to the screen$?$

FIGURE P33.49 shows the interference pattern on a screen $1.0m$behind a diffraction grating. The wavelength of the light is $620nm$. How many lines per millimeter does the grating have?

Light from a sodium lamp $\left(\lambda =589nm\right)$illuminates a narrow slit and is observed on a screen $75cm$behind the slit. The distance between the first and third dark fringes is $7.5mm$. What is the width (in $mm$) of the slit?

The wings of some beetles have closely spaced parallel lines of melanin, causing the wing to act as a reflection grating. Suppose sunlight shines straight onto a beetle wing. If the melanin lines on the wing are spaced $2.0\mu m$apart, what is the first-order diffraction angle for green light $\left(\lambda =550nm\right)$?

If sunlight shines straight onto a peacock feather, the feather appears bright blue when viewed from${15}^{\circ }$on either side of the incident beam of light. The blue color is due to diffraction from parallel rods of melanin in the feather barbules, as was shown in the photograph on page $940$. Other wavelengths in the incident light are diffracted at different angles, leaving only the blue light to be seen. The average wavelength of blue light is $470nm$. Assuming this to be the first-order diffraction, what is the spacing of the melanin rods in the feather?

You've found an unlabeled diffraction grating. Before you can use it, you need to know how many lines per it has. To find out, you illuminate the grating with light of several different wavelengths and then measure the distance between the two first-order bright fringes on a viewing screen $150cm$behind the grating. Your data are as follows:

Use the best-fit line of an appropriate graph to determine the number of lines per $mm$.

A diffraction grating has slit spacing $d$. Fringes are viewed on a screen at distance $L$. Find an expression for the wavelength of light that produces a first-order fringe on the viewing screen at distance$L$from the center of the screen.

FIGURE P33.56 shows the light intensity on a screen behind a single slit. The slit width is $0.20\mathrm{mm}$and the screen is $1.5\mathrm{m}$behind the slit. What is the wavelength (in nm) of the light?

FIGURE $P33.56$shows the light intensity on a screen behind a single slit. The wavelength of the light is$600\mathrm{nm}$and the slit width is $0.15\mathrm{mm}$. What is the distance from the slit to the screen?

FIGURE P33.56 shows the light intensity on a screen behind a single slit. The wavelength of the light is $600\mathrm{nm}$and the slit width is $0.15\mathrm{mm}$. What is the distance from the slit to the screen?