Uranium contains two isotopes, U-235 with an atomic mas of 235 g/mol, and u-238 with an atomic mass of 238g/mol. U-235 is needed as a fuel in nuclear reactors. Until recently, the method used to separate U-235 from U-238 was by gas diffusion. Use U-235 as R1, and
U-238 as R2 and determine the rate of diffusion and which gas will diffuse faster.

⚪︎U-235 diffused 10.01 times faster than U-238
⚪︎U-235 diffused 1.01 times slower than U-238
⚪︎U-235 effused 2.01 times slower than U-238
⚪︎U-235 effused 1.01 times faster than U-238
⚪︎U-235 diffused 1.01 times faster than U-238