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Chapter 30: Q.65 (page 873)

One possible concern with MRI (see Exercise 28) is turning the magnetic field on or off too quickly. Bodily fluids are conductors, and a changing magnetic field could cause electric currents to flow through the patient. Suppose a typical patient has a maximum cross section area of 0.060m2. What is the smallest time interval in which a 5.0Tmagnetic field can be turned on or off if the induced emfaround the patient's body must be kept to less than 0.10V??

Short Answer

Expert verified

The smallest time interval,dt=3s

Step by step solution

01

Step 1: 

The emf, is specified by Faradays, is the change in magnetic flux inside the loop, and it is given

ε=dΦmdt

The flux it through loop is the measure of magnetic field that flows through a loop of area A and is given by

Φm=BA

02

Magnetic Flux

We use the expression of Φm

ε=Ad(BA)dt=AdBdt

The values we provided for A,εanddB

dt=AdBε

=0.060m2(5T)0.10V

=3s

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