(a) Sodium ions (Na+) move at 0.865 m/s through a bloodstream in the arm of a person standing near a large magnet. The magnetic field has a strength of 0.255 T and makes an angle of 30.0° with the motion of the sodium ions. The arm contains 150 cm3 of blood with a concentration of 2.50×1020 Na+ ions per cubic centimetre. If no other ions were present in the arm, what would be the magnetic force on the arm?

(b) A cardiac pacemaker can be affected by static magnetic field as small as 1.7 mT. How close can a pacemaker wearer come to a long straight wire carrying 20A?

Question

(a)    Sodium ions (Na+) move at 0.865 m/s through a bloodstream in the arm of a person standing near a large magnet. The magnetic field has a strength of 0.255 T and makes an angle of 30.0° with the motion of the sodium ions. The arm contains 150 cm3 of blood with a concentration of 2.50×1020 Na+ ions per cubic centimetre. If no other ions were present in the arm, what would be the magnetic force on the arm?
 
(b)   A cardiac pacemaker can be affected by static magnetic field as small as 1.7 mT. How close can a pacemaker wearer come to a long straight wire carrying 20A?