The field at the centre of the current loop is given by, B =
oI/2R,
where R is the radius of the loop, I is the current in the loop and
o=
4
*10-7H/m
=> I = 2BR/ o=
3.82*10-7C
The magnetic field of the brain has been measured to be approximately 3.0x10-12 T. A simple...
The magnetic field of the brain has been measured to be approximately 3.0 ×10−12T. Although the currents that cause this field are quite complicated, we can get a rough estimate of their size by modeling them as a single circular current loop 16 cm (the width of a typical head) in diameter. What current is needed to produce such a field at the center of the loop?
The magnetic field around the head has been measured to be approximately 3.00×10−8 gauss . Although the currents that cause this field are quite complicated, we can get a rough estimate of their size by modeling them as a single circular current loop 16.0 cm (the width of a typical head) in diameter. What is the current needed to produce such a field at the center of the loop? Answer in A.
Magnetoencephalography (MEG) is a technique for measuring changes in the magnetic field of the brain caused by external stimuli such as touching the body or viewing images of food. Such a change in the field occurs due to electrical activity (current) in the brain. During the process, magnetic sensors are placed on the skin to measure the magnetic field at that location. Typical field strengths are a few femtoteslas (1 femtotesla=1 fT=10−15 T) . An adult brain is about 140...
Magnetoencephalography (MEG) is a technique for measuring
changes in the magnetic field of the brain caused by external
stimuli such as touching the body or viewing images of food. Such a
change in the field occurs due to electrical activity (current) in
the brain. During the process, magnetic sensors are placed on the
skin to measure the magnetic field at that location....
Magnetoencephalography (MEG) is a technique for measuring changes in the magnetic field of the brain caused by external...
Transcranial magnetic stimulation (TMS) is a noninvasive method to stimulate the brain using magnetic fields. It is used in treating strokes, Parkinson's disease, depression, and other physical conditions. In the procedure, a circular coil is placed on the side of the forehead to generate a magnetic field inside the brain. Although values can vary, a typical coil would be about 15 cm in diameter and contain 250 thin circular windings. The magnetic field in the cortex (3.0 cm from the...
Transcranial magnetic stimulation (TMS) is a noninvasive method to stimulate the brain using magnetic fields. It is used in treating strokes, Parkinson’s disease, depression, and other physical conditions. In the procedure, a circular coil is placed on the side of the forehead to generate a magnetic field inside the brain. Although values can vary, a typical coil would be about 15 cm in diameter and contain 250 thin circular windings. The magnetic field in the cortex (3.0 cm from the...
Typical field strengths are a few femoteslas (1fT=10^-15T). An adult brain is about 140mm wide, divided into two sections (called hemispheres) each about 70mm wide. We can model the current in one hemisphere as a circular loop, 65mm in diameter, just inside the brain. The sensor is placed so that it is along the axis of the loop 2.30cm from the center. A reasonable magnetic field is 4.35fT at the sensor. According to this model, what is the current in...
People have proposed driving motors with the earth's magnetic field. This is possible in principle, but the small field means that unrealistically large currents are needed to produce noticeable torques. Suppose a 17-cm-diameter loop of wire is oriented for maximum torque in the earth's field. What current would it need to carry in order to experience a very modest 1.0×10−3N⋅m torque?
The human nervous system is an electric system. In particular, our brains produce a mag- netic field of approximately B = 3pF. The currents responsible for this field are rather complicated, and not easy to map. Let us, however, estimate the size of theses currents. Model the brain’s electric network as a single circuit. Estimate the size of this circuit by measuring your head’s circumference, and compute the current in your brain
A magnetic field of 37.2 T has been achieved at the MIT Francis Bitter National Magnetic Laboratory. Find the current needed to achieve such a field(a) 2.00 cm from a long, straight wire;(b) At the center of a circular coil of radius 42.0 cm that has 100 turns;(c) Near the center of a solenoid with radius 2.40 cm, length 32.0 cm, and 40,000 turns.