Answers: 3
Physics, 21.06.2019 18:10, eweqwoewoji
Scientists use laser range-finding to measure the distance to the moon with great accuracy. a brief laser pulse is fired at the moon, then the time interval is measured until the "echo" is seen by a telescope. a laser beam spreads out as it travels because it diffracts through a circular exit as it leaves the laser. in order for the reflected light to be bright enough to detect, the laser spot on the moon must be no more than 1.0 km in diameter. staying within this diameter is accomplished by using a special large-diameter laser. part a if Ξ» = 540nm , what is the minimum diameter of the circular opening from which the laser beam emerges? the earth-moon distance is 384,000 km. express your answer to two significant figures and include the appropriate units.
Answers: 1
Physics, 22.06.2019 19:40, rileybaby34
Uranium has two naturally occurring isotopes. 238u has a natural abundance of 99.3% and 235u has an abundance of 0.7%. it is the rarer 235u that is needed for nuclear reactors. the isotopes are separated by forming uranium hexafluoride uf6, which is a gas, then allowing it to diffuse through a series of porous membranes. 235uf6 has a slightly larger rms speed than 238uf6 and diffuses slightly faster. many repetitions of this procedure gradually separate the two isotopes. what is the ratio of the rms speed of 235uf6 to that of 238uf6? express your answer to five significant figures.
Answers: 3
Physics, 22.06.2019 21:10, reinasuarez964
Which of the following is a measure of the amount of light a star directly emits? a. luminosity b. intensity c. wavelength d. brightness
Answers: 2
Physics, 23.06.2019 06:30, lilzaya510
Give an example for each of the following situations: 1) negative acceleration, but positive velocity 2) positive acceleration and positive velocity 3) positive acceleration, but negative velocity 4) negative acceleration and negative velocity 5) positive velocity and no acceleration
Answers: 1
Which is a possible result of higher air temperatures caused by global warming?
increase in sea lev...
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