Light from an incandescent source transmits through a polarizer whose transmission axis makes an angle of 37.0° with respect to the vertical; i. e., the 37.0 − ������ ���� on the polarizer lines up with the index mark on the component carrier. The light intensity after passing through the polarizer is 71.3 ���. (a) At what angle would you need to set a second polarizer in order to have no light transmitted through the second polarizer? (b) At what angle would you need to set the second polarizer to obtain a light intensity of 23.4 ���? Assume the polarizers are ideal.

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.