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6 Electric and Magnetic Fields in Life
6.8 In recording brain waves on the skull, at least three electrode contacts are made.
Why would two contacts not work very well?
6.9 When an electroencephalograph is used to monitor brain activity, how is an
alpha wave created?
6.10 An eel can stun prey with just a 600 V shock, but that same animal can suffer
a 100,000 V spark with little effect. Why is this?
6.11 If a person with a steel needle buried under her skin enters a MRI machine
with magnetic field gradient of 0.04 T/m, what force might be exerted on that needle
when it gains an induced magnetic moment of 50 J/T and it is aligned with the field?
6.12 Estimate the electric potential across an artery due to the Hall effect produced
an MRI field of 2 T, with a blood flow of 1 cm/s and an artery diameter of 1 mm.
6 Electric and Magnetic Fields in Life
6.8 In recording brain waves on the skull, at least three electrode contacts are made.
Why would two contacts not work very well?
6.9 When an electroencephalograph is used to monitor brain activity, how is an
alpha wave created?
6.10 An eel can stun prey with just a 600 V shock, but that same animal can suffer
a 100,000 V spark with little effect. Why is this?
6.11 If a person with a steel needle buried under her skin enters a MRI machine
with magnetic field gradient of 0.04 T/m, what force might be exerted on that needle
when it gains an induced magnetic moment of 50 J/T and it is aligned with the field?
6.12 Estimate the electric potential across an artery due to the Hall effect produced
an MRI field of 2 T, with a blood flow of 1 cm/s and an artery diameter of 1 mm.