Astudent is wearing a pair of sunglasses designed to reduce the glare from reflected surfaces. when the student tilts her head to the side and back again, she notices that the brightness of the blue sky changes in intensity. the student wonders why the intensity is affected by the orientation of her sunglasses. the light coming from the sky toward her sunglasses has most likely undergone a. absorption b. diffraction c. polarization d. refraction

Two trains leave a station at the same time, train a travels at a constant speed of 16 m/s. train b starts at 8.0 m/s but accelerates constantly at 1.0 m/s squared. after 10.0 seconds, which train has the greater speed?

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.

An atom that has gained or lost electrons is called an _