The brightness of a star is determined
a) only by its distance from earth
b) only by its size
c)by both is size and distance from earth
d) by its location in the night star

Utah's great salt lake has an average salinity seven times higher than that of the oceans. very few multicellular organisms live in this harsh environment. an example is the brine shrimp, which must devote a large portion of its metabolic energy to osmoregulation. these brine shrimp must available hint(s)utah's great salt lake has an average salinity seven times higher than that of the oceans. very few multicellular organisms live in this harsh environment. an example is the brine shrimp, which must devote a large portion of its metabolic energy to osmoregulation. these brine shrimp must pump water back into their cells to counter its loss due to osmosisactively pump water back out of their cells to counter its inflow due to osmosissynthesize membranes that are impermeable to substances that upset osmotic balanceactively pump salt back out of their cells to counter its inflow due to osmosis

Search coils and credit cards. one practical way to measure magnetic field strength uses a small, closely wound coil called a search coil. the coil is initially held with its plane perpendicular to a magnetic field. the coil is then either quickly rotated a quarter-turn about a diameter or quickly pulled out of the field. (a) derive the equation relating the total charge q that flows through a search coil to the magnetic-field magnitude b. the search coil has n turns, each with area a, and the flux through the coil is decreased from its initial maximum value to zero in a time ∆t. the resistance of the coil is r, and the total charge is q = i∆t, where i is the average current induced by the change in flux. (b) in a credit card reader, the magnetic strip on the back of a credit card is rapidly “swiped” past a coil within the reader. explain, using the same ideas that underlie the operation of a search coil, how the reader can decode the information stored in the pattern of magnetization on the strip. (c) is it necessary that the credit card be “swiped” through the reader at exactly the right speed? why or why not?

Exercise 2. find the wavelength of a photon emitted when an electron jumps from the n = 3 energy level down to the n = 2 energy level. where is this photon in the electromagnetic spectrum?