The magnitude J of the current density in a certain lab wire with a circular cross section of radius R ! 2.00 mm is given by J ! (3.00 $ 108)r2, with J in amperes per square meter and radial distance r in meters. What is the current through the outer section bounded by r ! 0.900R and r ! R

as we probably am aware that our atmosphere or air have various levels, each level has different gasses, and each gas has another porousness. at the point when the light originates from lower porousness to higher penetrability, it alters its course. with the goal that implies that when the light originates from the moon to the earth, it alters it's course a lot more occasions. it essentially implies that the state of the light piece of the moon is changed on the earth.

not copied too! hope this !

joke:

h o h o hope you have a merry christmas!

answer: 31, 5556. 952 seconds

snell's law

refractve index = sin incidence / sin refraction