Light travels at precisely <span>299,792,458 metres every second (abbreviated to 3 x 10^8 metres every second but let's be precise) There are 60 seconds in every minute (</span><span>299 792 458 x 60 = 17,987,547,480m) 60 minutes in every hour (17,987,547,480 x 60 = 1,079,252,849,000m) 96 hours in 4 days (</span><span>1,079,252,849,000 x 96 = 10,360,827,350,000m) </span><span>Now let's convert to km to make this number (slightly) more manageable (</span>10,360,827,350,000 / 1000 = <span>103,608,273,500km) </span>Light travels <span>103,608,273,500km in 4 days - that's the equivalent of going around the equator of the earth 813,124 times!</span><span>
Diffusion Coefficients can be calculated at different temperatures taking into account the energy of the diffusive process, remember that this process takes place in the interstices of the solid, and gets with higher temperatures due to the higher kinetic energy of the particles.