Question

A doctor is assisting with a patient’s MRI when the patient states he is feeling light-headed. The doctor rushes into the room and quickly reaches into the MRI to check the patient’s pulse and claims she could feel an effect on her ring when she reached into the MRI. You want to check the plausibility of her statement. You make the following assumptions: Her ring is about 2.5 cm in diameter. The MRI has a magnetic field of 5.4 Tesla inside and a magnetic field of zero where her hand started. It took about 0.5 seconds to reach inside the MRI, and her ring has a resistance of about 0.08 Ohms.

a) How much current is induced in her ring?

b)How much power is dissipated by her ring while she is reaching in?

Answer 1

Ring red = 2.5 = 1.25cm 2 B=5.4T at=0.5 R = 0.08 ohms & ;= B. A = BA=0 BA= 5.4 X TIX (+ 0125) 2, F weber o induced emf (E) 20 10.002651 -0 = 0.0053 volt 0.5 a) current induced i= &- 6.0053 R 0.66 Ampere. 0.08 b) Power dissipated =;2 R = (0.66)² x 0.08 = 0.034 84 & Watt