ELECTROMAGNETIC PHENOMENA1. Electromagnetic inductionMagnetic flux is a measurement of the total magnetic field B which passes through a givenarea. It is a useful tool for helping describe the effects of the magnetic force on somethingoccupying a given area. If the magnetic field is constant, the magnetic flux passing through asurface of area A is= B ·A coseNormal to AThe SI unit of magnetic flux is the Weber (Wb).Faraday lawWhen a current conducting wire or coil is moved through amagnetic field a voltage (EMF) is generated which depends onthe magnetic flux through the area of the coil. This is an exampleof the phenomenon of electromagnetic induction; the currentthat flows in this situation is known as an induced current.Faraday's Law relates the average induced EMF in terms of thetime rate of change of the total magnetic flux through a current8 cosBA cos e- B,Aconductor or coil.E = NAtFinally, if a coil has N turns, an emf will be produced that is N times greater than for a singlecoil, so that emf is directly proportional to N.The magnetic field strength (magnitude) produced by a long straight current-carryingwire is found by experiment to be B = , where I is the current, r is the shortest distance tothe wire, and the constant = 470x10 7T m/A is the permeability of free space.Magnetic field produced by a current-carrying circular loop. There is a simple formula forthe magnetic field strength at the center of a circular loop. It is B = where R is the radiusof the loop. One way to get a larger field is to have Nloops; then, the field is B = N.2. Electromagnetic fieldAt every instant the ratio of the magnitude of the electric field to the magnitude of the magneticfield in an electromagnetic wave equals the speed of light.2R"Emax EВтак в3. Electromagnetic wavesThe magnitudes electric field strength E and magnetic fieldstrength B in electromagnetic wave vary with x and iaccording to the expressionsE (x, t) = Egsin(kx – wt)B(x, t) = Bosin(kx – wt)Here k = and w =with 2 the wavelength and Tthe period of the wave (T=1/fwhere fis the frequency of oscillationof the wave). The speed of the wave is given by v = c = as /k.There are many types of waves, such as water waves and even earthquakes. Among the manyshared attributes of waves are propagation speed v, frequency f, and wavelength 2. These arealways related by the expression:v = af Electromagnetic waves, like visible light, infrared, ultraviolet, X-rays, and gamma rays don'tneed a medium in which to propagate; they can travel through a vacuum.Speed of electromagnetic wave in vacuumC =-Taking the permittivity of free space eo = 8.85 · 10-12 F/m and permeability of free space jto- 4T0x10 "Ťm/A, c = 3 · 10° m/sec.TaeLUeslenaspectTypeEMProductionApplicationswaveCommunicationsRemote controlsAcceg charges a themal Conmurictons Over Dep hegRadarRepas consband useRado& TVAcceng chargesMRIMicrowaesCell phoeThermal gtons & econThemal magngAbsorbed byamospherePhotonynhesis HumanhandGrente eectThermal agatons &econApeveThermal agkatons &elecon Seteton CancerOmne depleon CancercaingVnin DprotuctonMukal gsCancer therapyMekal gosCancer therapyoonteo sits ad Medkal Setyt cotCance cgCancer csgHaon dmgeNuckmedkinetiecutyCamma mysNucw decay4. Energy in electromagnetic waveElectromagnetic waves can bring energy into a system by virtue of their electric and magneticfields. These fields can exert forces and move charges in the system and, thus, do work on them.Once electromagnetic wave has created, the fields carry energy away from a source. IntensityI of electromagnetic wave is energy per area A per time t or power P per area. Intensity ismeasured in W/m²:1 = EnergyThe energy carried and the intensity I of an electromagnetic wave is proportional to E and B.In fact, for a continuous sinusoidal electromagnetic wave, the average intensity I is given bywhere c is the speed of light, a» is the permittivity of free space, and Eo is themaximum electric field strength.The average intensity of an electromagnetic wave I can also be expressed in terms of themagnetic field strength / =5. Radiation pressure is the pressure exerted upon any surface due to the exchange ofmomentum between the object and the electromagnetic field. The radiation pressure Pexertedon the perfectly absorbing surface is: P = {where Bo is the maximum magnetic field strength.6.The electromagnetic wave intensity at distance r from the source /:here Pis power.

Question
Asked Feb 12, 2020
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Give an order of magnitude estimate, based on Faraday’s law, of the maximum induced emf detected by a search coil with a 0.2 m diameter 1 cm away from a long neuron which carries an average current of 10 pA switched on in 1 ms. Suppose, that neuron is long straight current caring wire. 

ELECTROMAGNETIC PHENOMENA
1. Electromagnetic induction
Magnetic flux is a measurement of the total magnetic field B which passes through a given
area. It is a useful tool for helping describe the effects of the magnetic force on something
occupying a given area. If the magnetic field is constant, the magnetic flux passing through a
surface of area A is
= B ·A cose
Normal to A
The SI unit of magnetic flux is the Weber (Wb).
Faraday law
When a current conducting wire or coil is moved through a
magnetic field a voltage (EMF) is generated which depends on
the magnetic flux through the area of the coil. This is an example
of the phenomenon of electromagnetic induction; the current
that flows in this situation is known as an induced current.
Faraday's Law relates the average induced EMF in terms of the
time rate of change of the total magnetic flux through a current
8 cos
BA cos e- B,A
conductor or coil.
E = N
At
Finally, if a coil has N turns, an emf will be produced that is N times greater than for a single
coil, so that emf is directly proportional to N.
The magnetic field strength (magnitude) produced by a long straight current-carrying
wire is found by experiment to be B = , where I is the current, r is the shortest distance to
the wire, and the constant = 470x10 7T m/A is the permeability of free space.
Magnetic field produced by a current-carrying circular loop. There is a simple formula for
the magnetic field strength at the center of a circular loop. It is B = where R is the radius
of the loop. One way to get a larger field is to have Nloops; then, the field is B = N.
2. Electromagnetic field
At every instant the ratio of the magnitude of the electric field to the magnitude of the magnetic
field in an electromagnetic wave equals the speed of light.
2R"
Emax E
Втак в
3. Electromagnetic waves
The magnitudes electric field strength E and magnetic field
strength B in electromagnetic wave vary with x and i
according to the expressions
E (x, t) = Egsin(kx – wt)
B(x, t) = Bosin(kx – wt)
Here k = and w =
with 2 the wavelength and Tthe period of the wave (T=1/fwhere fis the frequency of oscillation
of the wave). The speed of the wave is given by v = c = as /k.
There are many types of waves, such as water waves and even earthquakes. Among the many
shared attributes of waves are propagation speed v, frequency f, and wavelength 2. These are
always related by the expression:
v = af
help_outline

Image Transcriptionclose

ELECTROMAGNETIC PHENOMENA 1. Electromagnetic induction Magnetic flux is a measurement of the total magnetic field B which passes through a given area. It is a useful tool for helping describe the effects of the magnetic force on something occupying a given area. If the magnetic field is constant, the magnetic flux passing through a surface of area A is = B ·A cose Normal to A The SI unit of magnetic flux is the Weber (Wb). Faraday law When a current conducting wire or coil is moved through a magnetic field a voltage (EMF) is generated which depends on the magnetic flux through the area of the coil. This is an example of the phenomenon of electromagnetic induction; the current that flows in this situation is known as an induced current. Faraday's Law relates the average induced EMF in terms of the time rate of change of the total magnetic flux through a current 8 cos BA cos e- B,A conductor or coil. E = N At Finally, if a coil has N turns, an emf will be produced that is N times greater than for a single coil, so that emf is directly proportional to N. The magnetic field strength (magnitude) produced by a long straight current-carrying wire is found by experiment to be B = , where I is the current, r is the shortest distance to the wire, and the constant = 470x10 7T m/A is the permeability of free space. Magnetic field produced by a current-carrying circular loop. There is a simple formula for the magnetic field strength at the center of a circular loop. It is B = where R is the radius of the loop. One way to get a larger field is to have Nloops; then, the field is B = N. 2. Electromagnetic field At every instant the ratio of the magnitude of the electric field to the magnitude of the magnetic field in an electromagnetic wave equals the speed of light. 2R" Emax E Втак в 3. Electromagnetic waves The magnitudes electric field strength E and magnetic field strength B in electromagnetic wave vary with x and i according to the expressions E (x, t) = Egsin(kx – wt) B(x, t) = Bosin(kx – wt) Here k = and w = with 2 the wavelength and Tthe period of the wave (T=1/fwhere fis the frequency of oscillation of the wave). The speed of the wave is given by v = c = as /k. There are many types of waves, such as water waves and even earthquakes. Among the many shared attributes of waves are propagation speed v, frequency f, and wavelength 2. These are always related by the expression: v = af

fullscreen
Electromagnetic waves, like visible light, infrared, ultraviolet, X-rays, and gamma rays don't
need a medium in which to propagate; they can travel through a vacuum.
Speed of electromagnetic wave in vacuum
C =-
Taking the permittivity of free space eo = 8.85 · 10-12 F/m and permeability of free space jto
- 4T0x10 "Ťm/A, c = 3 · 10° m/sec.
Tae
LUeslen
aspect
TypeEM
Production
Applications
wave
Communications
Remote controls
Acceg charges a themal Conmurictons Over Dep heg
Radar
Repas cons
band use
Rado& TV
Acceng charges
MRI
Microwaes
Cell phoe
Thermal gtons & econ
Themal magng
Absorbed by
amosphere
Photonynhesis Human
hand
Grente eect
Thermal agatons &econApeve
Thermal agkatons &elecon Seteton Cancer
Omne depleon Cancer
caing
Vnin Dprotucton
Mukal gs
Cancer therapy
Mekal gos
Cancer therapy
oon
teo sits ad Medkal Sety
t cot
Cance cg
Cancer csg
Haon dmge
Nuck
medkinetiecuty
Camma mys
Nucw decay
4. Energy in electromagnetic wave
Electromagnetic waves can bring energy into a system by virtue of their electric and magnetic
fields. These fields can exert forces and move charges in the system and, thus, do work on them.
Once electromagnetic wave has created, the fields carry energy away from a source. Intensity
I of electromagnetic wave is energy per area A per time t or power P per area. Intensity is
measured in W/m²:1 = Energy
The energy carried and the intensity I of an electromagnetic wave is proportional to E and B.
In fact, for a continuous sinusoidal electromagnetic wave, the average intensity I is given by
where c is the speed of light, a» is the permittivity of free space, and Eo is the
maximum electric field strength.
The average intensity of an electromagnetic wave I can also be expressed in terms of the
magnetic field strength / =
5. Radiation pressure is the pressure exerted upon any surface due to the exchange of
momentum between the object and the electromagnetic field. The radiation pressure Pexerted
on the perfectly absorbing surface is: P = {
where Bo is the maximum magnetic field strength.
6.
The electromagnetic wave intensity at distance r from the source /:
here P
is power.
help_outline

Image Transcriptionclose

Electromagnetic waves, like visible light, infrared, ultraviolet, X-rays, and gamma rays don't need a medium in which to propagate; they can travel through a vacuum. Speed of electromagnetic wave in vacuum C =- Taking the permittivity of free space eo = 8.85 · 10-12 F/m and permeability of free space jto - 4T0x10 "Ťm/A, c = 3 · 10° m/sec. Tae LUeslen aspect TypeEM Production Applications wave Communications Remote controls Acceg charges a themal Conmurictons Over Dep heg Radar Repas cons band use Rado& TV Acceng charges MRI Microwaes Cell phoe Thermal gtons & econ Themal magng Absorbed by amosphere Photonynhesis Human hand Grente eect Thermal agatons &econApeve Thermal agkatons &elecon Seteton Cancer Omne depleon Cancer caing Vnin Dprotucton Mukal gs Cancer therapy Mekal gos Cancer therapy oon teo sits ad Medkal Sety t cot Cance cg Cancer csg Haon dmge Nuck medkinetiecuty Camma mys Nucw decay 4. Energy in electromagnetic wave Electromagnetic waves can bring energy into a system by virtue of their electric and magnetic fields. These fields can exert forces and move charges in the system and, thus, do work on them. Once electromagnetic wave has created, the fields carry energy away from a source. Intensity I of electromagnetic wave is energy per area A per time t or power P per area. Intensity is measured in W/m²:1 = Energy The energy carried and the intensity I of an electromagnetic wave is proportional to E and B. In fact, for a continuous sinusoidal electromagnetic wave, the average intensity I is given by where c is the speed of light, a» is the permittivity of free space, and Eo is the maximum electric field strength. The average intensity of an electromagnetic wave I can also be expressed in terms of the magnetic field strength / = 5. Radiation pressure is the pressure exerted upon any surface due to the exchange of momentum between the object and the electromagnetic field. The radiation pressure Pexerted on the perfectly absorbing surface is: P = { where Bo is the maximum magnetic field strength. 6. The electromagnetic wave intensity at distance r from the source /: here P is power.

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Step 1

The given values are,

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Step 2

Write the expression for the induced electromotive force (emf).

Physics homework question answer, step 2, image 1

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