Cyclotrons are widely used in nuclear medicine for producing short-lived radioactive isotopes. these cyclotrons typically accelerate h− (the hydride ion, which has one proton and two electrons) to an energy of 5mev to 20mev. this ion has a mass very close to that of a proton because the electron mass is negligible−about 1/2000 of the protons mass. a typical magnetic field in such cyclotrons is 1.7 t .

part a

what is the speed of a 5.0-mev h−?

express your answer with the appropriate units.

part b

if the h− has energy 5.0mev and b= 1.7 t , what is the radius of this ions circular orbit?

express your answer with the appropriate units.

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.