A copper is 4 cm long at 10 Cº. The coefficient of linear expansion for copper is 1.7 x 10-5 (Cº)-1. Calculate the change in length (AL). when it is at 70 Cº.

Light from two different sources are incident upon the same side of a polarizing filter. light from one source is polarized with total intensity ip, while light from the other source is unpolarized with total intensity iu. as you rotate the polarizing filter through 360 degrees, the intensity of the transmitted light on the other side varies by a factor of 9. what is the relative intensity of the initial polarized source to the unpolarized source, or ip/iu?