As of right now, the universe is apparently composed of ________ visible baryonic matter, _________ undetectable "dark" matter, and __________ undetectable "dark" energy. (Fill in the missing blanks.)

a. 4 %, 23 %, 73 %
b. 30 %, 0 %, 70 %
c. 77 %, 23 %, 0 %
d. 73 %, 4 %, 23 %
e. 93 %, 3 %, 4 %


a.
Although the amount of visible matter seems small, observing conditions in our own universe (flatness, homogeneity, chemical composition, observed density) and extrapolation of that data lead to the above ratio.

Physics & Space Science

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A cyclic process is carried out on an ideal gas such that it returns to its initial state at the end of a cycle. If the process was carried out on a clockwise sense around the enclosed area, as shown on the p-V diagram in Fig

12-2, then that area represents A) the heat added to the ideal gas. B) the heat that flows from the ideal gas. C) the work done by the ideal gas. D) the work done on the ideal gas.

Physics & Space Science

A student adds two displacement vectors that have the magnitudes of 12.0 m and 5.0 m. What is the range of possible answers for the magnitude of the resultant vector?

What will be an ideal response?

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Calculate the half-value thickness (in mm) of lead if it reduces the intensity of a beam of x-rays whose wavelength is 10 pm by a factor of two. (Assume the linear absorption coefficient of lead is 43 cm?1 for x-rays of wavelength 10 × 10^?12 m.)

a. 0.24 b. 0.20 c. 0.12 d. 0.16 e. 0.18

Physics & Space Science

As air temperature cools below its dew point temperature, the air's water vapor

A) increases. B) decreases. C) condenses. D) evaporates.

Physics & Space Science