An Electromagnetic Flowmeter Is Useful When It Is Desirable Not $v$

Multiple Choice

An electromagnetic flowmeter is useful when it is desirable not to interrupt the system in which the fluid is flowing (such as the blood in an artery during heart surgery) . Such a device is illustrated in the figure. The conducting fluid moves with speed $v$ in a tube of diameter $d$ . Perpendicular to this tube is a magnetic field B. A voltage $V$ is induced between opposite sides of the tube due to the motion of the conducting fluid in the magnetic field. For a certain case, $B =$ $0.120 \mathrm {~T} , d = 1.2 \mathrm {~cm}$ , and the measured voltage is $V = 2.88 \mathrm { mV }$ . Determine the speed of the fluid.

A) $11 \mathrm {~m} / \mathrm { s }$
B) $750 \mathrm {~m} / \mathrm { s }$
C) $0.075 \mathrm {~m} / \mathrm { s }$
D) $1.1 \mathrm {~m} / \mathrm { s }$
E) $2.0 \mathrm {~m} / \mathrm { s }$