Question

Typical blood velocities in the coronary arteries range from 10 to 30 cm/s. An electromagnetic flowmeter applies a magnetic field of 0.27 T to a coronary artery with a blood velocity of 12 cm/s. As we can see in the figure below, this field exerts a force on ions in the blood, which will separate. The ions will separate until they make an electric field that exactly balances the magnetic force. This electric field produces a voltage that can be measured. https://imgur.com/a/9cgT4

Answer 1

The magnetic field B = 0.27 T

the velocity of the blood v = 12 cm/s

(a) The force is felt by singly ionized ion

              F = qvB sin?

here the velocity and magnetic field are perpendicular to each other

so      F = qvB

            = (1.6*10^-19C) ( 0.12 m/s) (0.27T)

            = 5.184*10^-21 N

(b) When the electric force due to electric field and magnetic force due to magnetic field are equal

               then   qE = qv B

                        

                          E = vB = (0.12m/s) (0.27T)

                              = 3.24*10^-2 V/m

(c) When the artery diameter is d = 2.6 mm

       then the voltage   V = Ed

                                     = (3.24*10^-2) (2.6*10^-3m)

                                     = 8.424*10^-5 V