Matter Waves: A crystal diffracts a beam of electrons, like a diffraction grating, as they hit it perpendicular to its surface. The crystal spacing is 0.18 nm, and the first maximum scattering occurs at 80° relative to the normal to the surface. (e = 1.60 × 10-19 C, melectron = 9.11 × 10-13 kg, h = 6.626 × 10-34 J ? s)(a) What is the wavelength of the electrons?(b) What potential difference accelerated the electrons if they started from rest?
Fill in the blank(s) with the appropriate word(s).
(a) 0.18 nm (b) 48 V
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Which planet had the Great Dark Spot in 1989, but had lost it by 1995?
A) Jupiter B) Saturn C) Mars D) Neptune E) Uranus
A compass needle is a magnet with a north and south pole. If a tiny compass were placed in the magnetic field shown in the figure, how would the compass needle aligned in the magnetic field?
a. The needle would line up with a magnetic field line with the compass needle pointing in the same direction as the arrows in the diagram. b. The needle would line up with a magnetic field line with the compass needle pointing in the opposite direction to the arrows in the diagram. c. The compass needle always aligns perpendicular to the magnetic field lines. d. The north pole of the compass will point directly at the north pole of the magnet, regardless of the field lines. e. The north pole of the compass will point directly away from the north pole of the magnet, regardless of the field lines.
At what rate is thermal energy generated in the 5-? resistor when ? = 24 V?
a.
13 W
b.
3.2 W
c.
23 W
d.
39 W
e.
51 W
What is a "super-Earth"?
A) a rocky planet that is more massive than Earth B) a rocky planet that has more water than Earth C) a jovian planet that is approximately the same mass as Earth D) a jovian planet that has a solid surface E) a rocky planet that is closer to its host star than Earth is to the Sun