You can measure the flow-rate of blood by applying a magnetic field to the blood and observing the forces felt by dierent ions moving in the bloodstream. For example, what force would you expect on a chlorine ion with single negative charge if you applied a magnetic field of 0.2 T? Assume you applied the magnetic field such that you observed maximal eect on the chlorine ion. What direction would this magnetic field be oriented? Note: there is more than one correct answer, just explain your reasoning. You can take blood to travel around 2mph in the body, which is on the slow-side, normal for blood in an extremity.

Suppose you wish to measure the current in a wire.  You have a device that can measure the strength of the magnetic field produced by the wire, but the device does not directly measure the current.  If the device is place 0.98m away from the wire, and the magnetic field strength is 1.72μ T, what is the current running through the wire in Amps? Note:  It is understood that the unit of your answer is in A, however do not explicitly include units in your answer.

A velocity selector in a mass spectrometer uses a 0.130 T magnetic field.  a. What electric field strength (in volts per meter) is needed to select a speed of 3.70 ✕ 106 m/s?  b. What is the voltage (in kilovolts) between the plates if they are separated by 1.00 cm?