Certain planes of a crystal of halite have a spacing of 0.399 nm. The crystal is irradiated by a beam of x-rays. First order constructive interference occurs when the beam makes an angle of 20° with the planes of the crystal surface
What is the wavelength of the x-rays?
A) 0.24 nm B) 0.27 nm C) 0.17 nm D) 0.14 nm E) 0.21 nm
B
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Light of wavelength 687 nm is incident on a single slit 0.75 mm wide. At what distance from the slit should a screen be placed if the second dark fringe in the diffraction pattern is to be 1.7 mm from the center of the screen?
A) 0.39 m B) 0.47 m C) 0.93 m D) 1.1 m E) 1.9 m
An uncharged metal sphere is placed on an insulating puck on a frictionless table. While being held parallel to the table, a rod with a charge q is brought close to the sphere, but does not touch it. As the rod is brought in, the sphere
a. remains at rest. b. moves toward the rod. c. moves away from the rod. d. moves perpendicular to the velocity vector of the rod. e. moves upward off the puck.
Unpolarized light of intensity I passes through four Polaroid sheets whose polarizing angles are rotated 30° from each other so that the last sheet is aligned at 90° to the first. What is the intensity of the light emerging from the fourth sheet?
What will be an ideal response?
The eerie and pretty northern and southern lights that are produced when gases in Earth's upper atmosphere glow from energy delivered by the solar wind are referred to as _____
A) aurorae B) coronal holes C) solar flares D) spicules