A crystal diffracted a beam of electrons. The crystal spacing was 0.18 nm and the maximum scattering occurred at 80.° relative to the surface normal. The electrons were directed normally onto the crystal
(a) What is the wavelength of the electrons? (b) What potential difference accelerated the electrons?
(a) 0.18 nm
(b) 48. V
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The energy of a body moving across a horizontal surface is an example of __________ energy
Fill in the blank(s) with correct word
GIVEN ? A disk rotating in air ? Diameter (D) = 2 m ? Rotational speed (?) = 600 rev/min ? Air temperature (T?) = 20°C ? Surface temperature (Ts) = 50°C FIND ? The rate of heat transfer from one side (q) ASSUMPTIONS ? The heat transfer has reached steady state ? The disk is horizontal ? Air is still SKETCH
GIVEN
? A disk rotating in air
? Diameter (D) = 2 m
? Rotational speed (?) = 600 rev/min
? Air temperature (T?) = 20°C
? Surface temperature (Ts) = 50°C
FIND
? The rate of heat transfer from one side (q)
ASSUMPTIONS
? The heat transfer has reached steady state
? The disk is horizontal
? Air is still
SKETCH
PROPERTIES AND CONSTANTS
From Appendix 2, Table 28, for dry air at the mean temperature of 35°C
Soil forming factors include
What will be an ideal response?
The energy needed to change a He+ ion in the ground state into a He2+ ion is
a. 13.6 eV b. 54.4 eV c. 112.4 eV d. 92.9 eV e. 27.2 eV