Arsenic diffusion in si: arsenic is diffused into a thick slice of silicon with no previous arsenic in it at 1100ºc. if the surface concentration of the arsenic is 5.0 × 1018 atoms/cm3 and its concentration at 1.2 µm below the silicon surface is 1.5 × 1016 atoms/cm3 , how long must be the diffusion time? (d = 3.0 × 10-14 cm2 /s for as diffusing in si at 1100ºc.)

Which of the following correctly describes the early view of catastrophism?

Why do electron microscopes have higher resolving power than light microscopes?

During physical science, ms. greene challenged her students to produce an energy transformation. james and jill wrapped a 4-inch nail with a coil of fifty turns of wire. they connected one end of the coil to one terminal of a knife switch. they connected the other terminal of the knife switch to the battery. finally, they connected the end of the coil to the other terminal of the battery. james held the tip of a 1-inch nail near the flat end of the 4-inch nail. jill closed the knife switch quickly and then opened it. the 1-inch nail was pulled toward the 4-inch nail. what is the best explanation of why the nail moved? a) electrical energy was converted to mechanical energy in the 1-inch nail. b) the 4-inch nail became an electromagnet and the magnetic force attracted the 1-inch nail. c) the electric current in the 4-inch nail was converted to mechanical energy in the 1-inch nail. d) the 4-inch nail had a positive charge and the 1-inch nail had a negative charge. opposites attracted.