research group uses short bursts of laser light to measure the motion of electrons moving within and among atoms. In the planetary model of the atom, the hydrogen atom can be viewed as having a single electron in a circular orbit with a diameter of approximately 10-10 m. If the average speed of the electron in the orbit is known to be 2,200,000 m/s, calculate the number of revolutions per second it makes around the nucleus.

Cells in the nervous system have a potential difference of 70 mv across the cell membrane separating the interior of the cell from the extracellular fluid. this potential difference is maintained by ion pumps that move charged ions across the membrane. is this an emf? select the correct answer and explanation. 1)no. the ion pumps cannot separate charges; thus, they cannot create a potential difference. 2)yes. the ion pumps cannot separate charges, but they still can create a potential difference. 3)yes. the ion pumps can actively separate charge; thus, they can create a potential difference. 4)no. the ion pumps can separate charges, but they cannot create a potential difference.