Problem: Hydrogen is commonly used in power stations as a coolant in generators due to a number of favorable properties that are a direct result of its light diatomic molecules. These include low density, low viscosity, and the highest specific heat and thermal conductivity of all gases.
Why is it used as a coolant?
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Answer: favorable properties that are a direct result of its light diatomic molecules


Problem: Underpinning Houston's land surface are unconsolidated clays, clay shales, and poorly cemented sands up to several miles deep. The region's geology developed from river deposits formed from the erosion of the Rocky Mountains. These sediments consist of a series of sands and clays deposited on decaying organic marine matter, that over time, transformed into oil and natural gas. Beneath the layers of sediment is a water-deposited layer of halite, a rock salt. The porous layers were compressed over time and forced upward. As it pushed upward, the salt dragged surrounding sediments into salt dome formations, often trapping oil and gas that seeped from the surrounding porous sands. The thick, rich, sometimes black, surface soil is suitable for rice farming in suburban outskirts where the city continues to grow.
The glass deposited onto decaying marine matter transformed into what?
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Answer: unanswerable


Problem: The difference in the above factors for the case of θ=0 is the reason that most broadcasting (transmissions intended for the public) uses vertical polarization. For receivers near the ground, horizontally polarized transmissions suffer cancellation. For best reception the receiving antennas for these signals are likewise vertically polarized. In some applications where the receiving antenna must work in any position, as in mobile phones, the base station antennas use mixed polarization, such as linear polarization at an angle (with both vertical and horizontal components) or circular polarization.
What is one use that would require an antenna to receive signals in various ways at once?
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Answer:
mobile phones