Which statements describe intensity? Check all that apply. Intensity is the amount of energy that flows in an area per unit of time. Intensity is the number of wavelengths that flow in an area per unit of time. Intensity that is lower than or equal to 85 units can harm human hearing. Intensity that is greater than or equal to 85 units can harm human hearing. Intensity is measured in decibels. Intensity is measured in hertz.

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.