The rare-Earth hypothesis would predict that the factor flife, in the Drake equation should be close to
A) 0
B) 0.25
C) 1
D) 0.5
A
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How far above the horizon is the Moon when its image reflected in calm water is completely polarized? (nwater = 1.333)
a. 53.12° b. 18.44° c. 22.20° d. 36.88°
If a person in Alaska were locked out of his house on a day when the temperature outside was ?40°C, his thick clothing would mostly reduce the loss of thermal energy by
a. conduction. b. convection. c. radiation. d. all of the above. e. convection and radiation.
In the SI, weight is expressed in units of ______________
Fill in the blank(s) with correct word
A photocathode whose work function is 2.9 eV is illuminated with white light that has a continuous wavelength band from 400 nm to 700 nm
What is the range of the wavelength band in this white light illumination for which photoelectrons are not produced?(c = 3.00 × 108 m/s, h = 6.626 × 10-34 J ? s, 1 eV = 1.60 × 10-19 J) A) 430 nm to 700 nm B) 400 nm to 480 nm C) 430 nm to 480 nm D) 400 nm to 430 nm E) 480 nm to 700 nm