Changing the f-number of a camera by two stops by going from f/16 to f/8 will change the intensity of the light hitting the film by a factor of:
a. 4.
c. 1/4.
b. 1/2.
d. 2.
A
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The sketch shows groups of stars on the H-R diagram, labeled (a) through (e); note that (a) represents the entire main sequence, while (c) and (d) represent only small parts of the main sequence. Which group represents stars with the longest main-sequence lifetimes?
A) a B) b C) c D) d E) e
What size capacitor should be placed in series with a 30-? resistor and a 40-mH inductive coil if the resonant frequency of the circuit is to be 1.0 kHz?
A) 3.3 µF B) 0.63 µF C) 6.0 µF D) 4.5 µF E) 2.0 µF
What is the minimum energy an incoming electron must have to knock a K shell electron out of an atom of molybdenum (Z = 42)?
A) 10.1 × 103 eV B) 11.3 × 103 eV C) 22.9 × 103 eV D) 34.4 × 103 eV E) 44.0 × 103 eV
A star with an apparent magnitude of 10 appears fainter than a star with an apparent magnitude of 9
Indicate whether the statement is true or false