Using an electromagnetic flow meter (Figure), a heart surgeon monitors the flow rate of blood through an

Question:

Using an electromagnetic flow meter (Figure), a heart surgeon monitors the flow rate of blood through an artery. Electrodes A and B make contact with the outer surface of the blood vessel, which has interior diameter 3.00 mm.(a) For a magnetic field magnitude of 0.040 0 T, a potential difference of 160 ?V appears between the electrodes. Calculate the speed of the blood.(b) Verify that electrode A is positive, as shown. Does the sign of the emf depend on whether the mobile ions in the blood are predominantly positively or negatively charged?Explain.