Electromagnetic waves used in cell phones are called a. radio waves
b. microwaves
c. Gamma rays
d. Ultraviolet rays

Asheet of steel 1.5 mm thick has nitrogen atmospheres on both sides at 1200oc and is permitted to achieve a steady-state diffusion condition. the diffusion coefficient for nitrogen in steel at this temperature is 6 x 10- 11 m2 /s, and the diffusion flux is found to be 1.2 x 10-7 kg/m2 -s. also, it is known that the concentration of nitrogen in the steel at the high-pressure surface is 4 kg/m3 . how far into the sheet from this high-pressure side will the concentration be 2.0 kg/m3 ? assume a linear concentration profile.

Which of the following are used in an electrochemical cell? a. electrodes b. electrolyte c. terminals d. all of the above

Which planet do you think would be easiest for humans to colonize some day?