Hydrogen lines are weak in the spectra of hot stars because many of the hydrogen atoms have their electrons in levels above the second level
a. True
b. False
Indicate whether the statement is true or false
True
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The unit of work, joule, is dimensionally the same as:
a. newton/second. b. newton/kilogram. c. newton-second. d. newton-meter.
State the principle of superposition
What will be an ideal response?
A battery has an internal resistance of 4.0 ?. Which of the following load resistors would have the most power delivered to it when connected across the battery?
A. 1.4 ? B. 2.0 ? C. 4.0 ? D. 8.0 ? E. 16 ?
A crystal is irradiated with x-rays with a wavelength of 0.120 nm. The atomic planes in the crystal are separated by 0.21 nm. At what angles of incidence with respect to the normal will the x-rays reflect from the crystal?
A) only 73° B) only 55° C) only 73° and 31° D) 73°, 55°, 31°