Determine the amount of energy carried in 2.0 m of a 4.6-mW He-Ne laser beam if the cross-sectional area of the beam is 4.1 × 10^?6 m2
a. 1.4E–10 J
b. 4.9E–12 J
c. 3.1E–11 J
d. 6.1E–8 J
e. 1.0E–11 J
c
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What do the radio pulses within the anticoded message sent in 1974 represent?
a. all the letters in the alphabet b. dots and dashes, like Morse code c. binary numbers, ones and zeroes d. Music, notes and measures e. the numbers one through ten
Suppose Earth's rotation axis were tilted by 45 degrees instead of 23.5 degrees. How would the number of daylight hours be different on December 21 in the United States (or any northern hemisphere country)?
A) There would be more hours of daylight than we have with a 23.5 degree tilt. B) There would be fewer hours of daylight than we have with a 23.5 degree tilt. C) The number of daylight hours would be about the same as it is if its tilt were 23.5 degrees.
Would it be plausible for a planet that had an Earth-like atmosphere with plentiful oxygen, but no life of any kind, to exist in another solar system?
a. Plausible. Life requires far more than oxygen to exist. b. Plausible. The oxygen may have been transported there by cometary impacts. c. Implausible. Oxygen is highly reactive and its presence in an atmosphere suggests replenishment by a living organism of some sort. d. Implausible. Oxygen is essential to life.
A component in an automobile 12-V electrical system has a resistance of 90 ?. How much current is in the component when in operation?
a. 100 A b. 0.13 A c. 7.5 A d. 1100 A