Thickness of Human Hair. Although we have discussed single-slit diffraction only for a slit, a similar result holds when light bends around a straight, thin object, such as a strand of hair. In that case, a is the width of the strand. From actual laboratory measurements on a human hair, it was found that when a beam of light of wavelength 632.8 nm was shone on a single strand of hair, and the diffracted light was viewed on a screen 1.25 m away, the first dark fringes on either side of the central bright spot were 5.22 cm apart. How thick was this strand of hair?

Thickness of Human Hair. Although we have discussed single-slit diffraction only for a slit, a similar result holds when light bends around a straight, thin object, such as a strand of hair. In that case, a is the width of the strand. From actual laboratory measurements on a human hair, it was found that when a beam of light of wavelength 632.8 nm was shone on a single strand of hair, and the diffracted light was viewed on a screen 1.25 m away, the first dark fringes on either side of the central bright spot were 5.22 cm apart. How thick was this strand of hair?

Physics for Scientists and Engineers: Foundations and Connections

1st Edition

ISBN:9781133939146

Author:Katz, Debora M.

Publisher:Katz, Debora M.

Chapter35: Diffraction And Interference

Section: Chapter Questions

Problem 40PQ

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Although we have discussed single-slit diffraction only for a slit, a similar result holds when light bends around a straight, thin object, such as a strand of hair. In that case, a is the width of the strand. From actual lab measurements on a human hair, it was found that when a beam of light of wavelength 632.8nm was shone on a single strand of hair, and the diffracted light was viewed on a screen 1.25m away, the first dark fringes on either side of the central bright spot were 5.22cm apart. How thick was this strand of hair?
In a Young's double-slit experiment, the separation between slits is d and the screen is a distance R from the slits. R is much greater than d and > is the wavelength of the light. The number of bright fringes per unit width on the screen is: d/RX R/dλ Rd/λ X/Rd Rλ/d
In a double slit experiment, what is the path difference between two waves that create the third bright band (m=3) from the central bright band? 0.5λ λ 1.5λ 2λ 3λ
In Young's double slit experiment with a monochromatic light of wavelength 4000A°, the fringe width is found to be 0.4 mm. When the slits are now illuminated with a light of wavelength 5000A° the fringe width will be 1) 0.32mm 2) 0.5mm 7. 3) 0.6mm 4) 0.8mm
Consider a double-slit diffraction experiment with slits of width 0.260 mm. Monochromatic light of wavelength 435 nm is used. If the value of the parameter for a point that is an angular distance of 0.0120 rad from the center of the central diffraction peak is 31.76 rad, what must be the slit separation (in mm)?
Diffraction can be used to provide a quick test of the size of red blood cells. Blood is smeared onto a slide, and a laser shines through the slide. The size of the cells is very consistent, so the multiple diffraction patterns overlap and produce an overall pattern that is similar to what a single cell would produce. Ideally, the diameter of a red blood cell should be between 7.5 and 8.0 μm. If a 633 nm laser shines through a slide and produces a pattern on a screen 24.0 cm distant, what range of sizes of the central maximum should be expected? Values outside this range might indicate a health concern and warrant further study.
In a modified Young's double slit experiment, a monochromatic uniform and parallel beam of light of wavelength 6000 A and intensity (10/) Wm2 is incident normally on two apertures A and B of radii 0.001 m and 0.002 m respectively. A perfectly transparent film of thickness 2000 A and refractive index 1.5 for the wavelength of 6000A is placed in front of aperture A (see figure). Calculate the power (in W) received at the focal spot F of the lens. The lens is symmetrically placed with respect to the apertures. Assume that 10% of the power received by each aperture goes in the original direction and is brought to the focal spot.
In the figure, first-order reflection from the reflection planes shown occurs when an x-ray beam of wavelength 0.820 nm makes an angle θ = 62.3˚ with the top face of the crystal. What is the unit cell size a0?
In a Young's double slit experiment set úp, slits are kept 0.4 mm apart from each other and screen is kept 2 m apart from slit. The fringe for a given monochromatic light is 0.8 mm. If the whole set up is kept in medium of refractive index 1.6, the fringe width becomes.
Monochromatic X-rays are incident on a crystal. The first-order Bragg peak is observed when the angle of incidence is 34.0°. The crystal spacing is known to be 0.347 nm. What is the wavelength of the X rays?
Q/4 : In Biprism experiment the fringe width is 0.30 mm. If slits are covered by glass plate of thickness 0.04 mm and refractive index u = 1.5, then the fringe width is (a) 0.02 mm (b) 0.1 mm (c) 0.30 mm (d) 0.2 mm
In a double slit experiment, the distance between the slit is 1 mm and screen is 25 cm away from the slits. The wavelength of light is 6000 Å. The width of the finge on the screen is