What is Field strength: Definition and 367 Discussions

In physics, field strength means the magnitude of a vector-valued field (e.g., in volts per meter, V/m, for an electric field E).
For example, an electromagnetic field results in both electric field strength and magnetic field strength.
As an application, in radio frequency telecommunications, the signal strength excites a receiving antenna and thereby induces a voltage at a specific frequency and polarization in order to provide an input signal to a radio receiver. Field strength meters are used for such applications as cellular, broadcasting, wi-fi and a wide variety of other radio-related applications.

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  1. K

    Can Electric Field Strength describe the Electric Field?

    We have two difference electric fields A and B. We are standing at point W1 in field A and the potential at a point M1 which is 0.5 meter left is 10 volts while the potential at point M2, which is 0.5 meter right, is 5volts. The potential difference between M1 and M2 is 5volts and the strength...
  2. D

    Relationship between magnetic field strength and voltage

    So I'm really confused with the relationship between magnetic field strength and voltage. Say you have a battery (with a DC voltage) with 4 coils, when voltage increases, does magnetic field strength increase? Is there any law (i.e. Faraday's law) that supports this?
  3. B

    Solving for Electric Field Strength

    Homework Statement An electric dipole is formed from 1.0 nC charges spaced 2.4 mm apart. The dipole is at the origin, oriented along they-axis. What is the electric field strength at the following points? a. (x, y) = (10 cm, 0 cm) b. (x, y) = (0 cm, 10 cm)Homework Equations Pythagorean Theorem...
  4. S

    Net Electric Field Strength at a Point due to a Uniform Electric Field

    Homework Statement A uniform electric field exists everywhere in the x, y plane. This electric field has a magnitude of 3600 N/C and is directed in the positive x direction. A point charge -9.8 × 10-9 C is placed at the origin. Find the magnitude of the net electric field at y = +0.20...
  5. J

    Homework, electric field strength at centre of a square

    Homework Statement 4 charges of +5µC, +3µC, -4µC and +2µC form the 4 points of a square of side length 2m. Calculate the field strength and potential at the centre of the square. Homework Equations F=1/4πhttp://upload.wikimedia.org/math/d/3/c/d3c305fc416b971cd6d284564e51bf85.png0 X Q1Q2/r2 E=...
  6. C

    Magnetic Field Strength Vs. Angle of direction

    I have a simple question... does the magnetic field angle of direction vary when you vary the field strength? For example, say i have a magnetoresistive sensor, which, to my knowledge only detects the magnetic field angle of direction (unlike a halls, which senses field strength). I place...
  7. S

    Surface Area and electric field strength

    This is my first post but I have frequented the forum for a little while now. I tried to figure things out myself and often times I am lead here by google. So my question is this: How is the electric field of an object altered when the surface area of the object is altered? Example: Take a...
  8. P

    Electric field strength from two charges

    Homework Statement Two identical point charges, q1 = +2.5 x 10-6 C and q2 = +2.5 x 10-6 C, are placed as shown in the diagram below. Point P is a distance 0.05 m from q1 and 0.12 m from q2, such that the angle at P is 90 degrees. Calculate the magnitude of the Electric field E at point P...
  9. N

    How does a dielectric increase maximum electric field strength?

    Homework Statement How does a dielectric increase maximum electric field strength? From the two cases where a dielectric is inserted into a charged capacitor after it is disconnected and after it is remained connected it seems that E will either decrease or stay the same. But I read in...
  10. A

    Electric field strength at the center of an equilateral triangle

    Homework Statement 3 rods each of length 1 meter form an equilateral triangle. Two rods have a uniform charge distribution of 8\times 10^{-6} C and the third of -8\times 10^{-6} C. What is the electric field strength at the center of an equilateral triangle Homework Equations \vec{E} =...
  11. R

    Concerning differentials in electric field strength calculations

    Hi guys, first time posting here, but I have a question that I have been thinking about for quite a while, and I hope someone can help out with it. Assume a line of charge (with overall charge of +Q and of length L) that is lying on the x-axis. You want to calculate the electric field strength...
  12. J

    Magnetic field strength that emits waves

    Homework Statement The microwaves in a microwave oven are produced in a special tube called a magnetron. The electrons orbit the magnetic field at 2.99GHz, and as they do so they emit 2.99GHz electromagnetic waves. What is the magnetic field strength? Homework Equations ƒ=qβ/(2Pi*m) Thus...
  13. J

    Magnetic field strength and magnetic flux

    Hi, please could someone help with my confusion over these two qauntities. In class we recently learned that magnetic field strength (B) is the number of flux lines (measured in Webers) per square metre. The magnetic flux on the other hand is the total number of flux lines (measured in Webers)...
  14. Quarlep

    Gravitational Field Strength due to a Uniform Rod

    I am trying to learn Physics an dI am reading a booK about classical mechanics.I a stuck somewhere in there If you know a gravitational force to a uniform rod I saw there a x and dx Why we need them ? Thanks!
  15. B

    What is the net electric field at point P in this physics problem?

    Physics Problem , please help I'm writing a test tomorrow and want to know if I'm right. The Question : Two point charges Q1 and Q2 are spaced 3m apart. Q1's charge = 14C Q2's charge = +20 C *Q1 -------(3meters)------- *Q2 ----(2meters)---- *P Calculate the net electric field at...
  16. H

    Relationship between gravitational field strength and potential

    Hi, I am a bit confused with the relationship between gravitational field strength and gravitational potential. As far as I know, gravitational field strength is defined as: g=\frac{F}{m}=\frac{GM}{R^{2}} and gravitational potential is defined as: V=\frac{-GM}{R} Now if I...
  17. D

    Calculating how magnetic field strength decreases with distance

    Hi everyone, I am trying to calculate the decrease in magnetic field strength over distance, using a formula I found on this thread https://www.physicsforums.com/showthread.php?t=522223 The formula given was 1/r^3, where r is the distance from the source. The same thread says the formula...
  18. T

    Ampere's Law - Magnetic Field Strength

    Homework Statement Use Ampere's Law to show that the magnetic fi eld strength at a distance R from a long, straight wire, carrying a current I, is: H = I/2\piR Homework Equations F=qVB B=\mu0I/2\piR The Attempt at a Solution I'm not sure how to answer this question. I got the...
  19. Q

    Electric field strength goes to 0

    Homework Statement Two point charges lie on the x-axis. Charge Q1= +7 μC is located at x = 0 and charge Q2 = -18μC is located at x = 25 cm. Find the point on the x-axis (in cm) where the net electric field is zero. Homework Equations E = F/C F = k(q1)(q2)/r^2 The Attempt at a Solution Okay...
  20. I

    Magnetic Field Strength versus Coil Density

    Homework Statement We did a lab where we measured the magnetic field strength of a wire coil versus the coil density of the wire coil, keeping current constant. We determined the relationship of B (magnetic field strength) versus n (coil density) to be direct. I need to explain why this is...
  21. L

    Simple electric field strength problem

    Homework Statement How far away from a 360μC charged particle is the electric field strength 49mN/C? Homework Equations E=(8.99x10^{9} x \frac{Q}{r^{2}} The Attempt at a Solution I assumed it would be a simple case of rearranging the equation to give r=\sqrt{\frac{8.99x10^{9}xQ}{E}}...
  22. C

    The magnetic field strength required to oscillate an electron

    Homework Statement "An electron is accelerated by a potential difference of 1 V and is injected into vacuum. How strong should the magnetic field in a vacuum be if you want the electron to circle along a loop with a radius of 10^-1m? Please indicate the direction of the magnetic field"...
  23. N

    Electric field strength at the center of semicircle

    Homework Statement A uniformly charged insulating rod of length 12.0 cm is bent into the shape of a semicircle as shown in the figure below. The rod has a total charge of −7.50 µC. Find the magnitude of the electric field at O, the centre of the semicircle. Homework Equations E = 2kq /...
  24. N

    Electric Field strength between 3 charges and directions

    Homework Statement Three point charges lie along a straight line as shown in the figure below, where q1 = 6.36 µC, q2 = 1.57 µC and q3 = −1.82 µC. The separation distances are d1 = 3.00 cm and d2 = 2.00 cm. Calculate the magnitude and direction of the net electric force on each of the...
  25. N

    Electric field strength of 4 charges positioned in a square shape

    Homework Statement Four charged particles are at the corners of a square of side a as shown in the figure below. (Let A = 3, B = 5 and C = 6.) (a) Determine the electric field at the location of charge q. (Use the following as necessary: q, a, and ke.) (b) Determine the total...
  26. D

    How to predict a magnet's field strength?

    Hi, I am interested in making my own (weak) magnets exposing some ferrous metal to the magnetic field of an electromagnet, but this is theoretical rather than something I am able to actually do right now. I am wondering if there are any formulas that can help calculate/estimate the resulting...
  27. M

    Three layers of a capacitor - Voltage divider + field strength.

    Homework Statement In a plate capacitor, the plates has a area of ##100cm^2## and a distance of 3mm. The insulation between the plates is a 1mm glass plate (εr = 10), a 0.5mm thick mica plate (εr = 5) and the rest is air. The insulation layers is parallel with the capacitor plates. The...
  28. M

    Calculating Field Strength in a Plate Capacitor

    Homework Statement The insulation in a plate capacitor consists of two layers with the thickness of 1 and 2 mm, and a relative permittivity of 4 and 6. Calculate the field strength in the thinnest layer when the capacitor is connected to a voltage of 5000v. Homework Equations The...
  29. L

    Electric Field Strength Between Two Parallel Plates Problem

    Homework Statement If the electric field strength between two parallel plates 1cm apart is 3.1kN/C, how much energy will be used by the electric field to move an electron (placed half way between the plates) 3mm nearer to the positively charged plate? Homework Equations Work Done =...
  30. C

    Electric field strength and particle deflection

    Homework Statement A proton enters the gap between a pair of metal plates (an electrostatic separator) that produces a uniform, vertical electric field between them. Ignore the effect of gravity on the proton. a) Assuming that the length of the plates is 11.1cm , and that the proton will...
  31. C

    Where Does the Electric Field Cancel Between Two Unequal Charges?

    Two isolated point charges -7μC and +2μC are at a fixed distance apart. At which point is is it possible for the electric field strength to be zero? I don't know where to start with only 2 numbers and no distances. I know that E= kQ/r^2
  32. A

    Field strength tensor / matrix

    In my note, we have written the field strength tensor as: F^{\mu\nu} =\partial ^\mu A^\nu -\partial ^\nu A^\mu = \begin{pmatrix} 0&E_x &E_y&E_z \\ -E_x&0 &B_z &-B_y \\ -E_y&-B_z &0 &B_x \\ -E_z&B_y &-B_x&0 \end{pmatrix} But if I look into...
  33. Crazymechanic

    What is the maximum magnetic field strength for a given size permanent magnet?

    Now I'm sure one can find this at google somehow , even though I wasn't that successful with it. Does someone know what is the highest magnetic field strength for a givem size permanent magnet for example? Like a 1cm ball of neodymium or some other material, what would be the highest field...
  34. C

    Calculating Net Electric Field Strength at Point A

    Homework Statement Find the net electric field strength at point A due to the combined electric fields of both charges. Homework Equations E=kq/d^2 The Attempt at a Solution I know how to solve these type of problems however I'm just wondering how come in the net force line as you...
  35. L

    Calculating magnetic field strength through objects.

    If I have a magnetic field of say 5 Tesla which is 3m from a concrete wall 0.25m thick how would I go about calculating the strength of the magnetic field on the other side of the wall? Any help/guidance much appreciated!
  36. R

    Electric Field Strength Between Two Charges

    Homework Statement Two isolated point charges, -7 μC and +2 μC, are at a fixed distance apart. At which point is it possible for the electric field strength to be zero? (A)......(B)...(C).....(D) o----------------------o----------o---------------o ......-7 μC...+2 μC...
  37. M

    Field strength is the potential gradient graph question

    Homework Statement By use of the graph in part (a), calculate the gravitational field strength at a distance 2R from the centre of the Earth. Homework Equations g = delta V / Delta r filed strength is the potential gradient The Attempt at a Solution I have drawn the...
  38. Crazymechanic

    What limits the strength of a field at a given point in space?

    Ok even though Vanadium recently asked me to stop this stupid way of learning something through asking the same questions , even though their not all the same , I'll try my cards with this one.Ok so we have fields like gravitational, electric and magnetic , now theoretically the fields don't...
  39. E

    Relation Between the Magnetic Field Strength and Distance

    Hey guys, I have recently performed a lab where we are to find the equation relating the magnetic field strength to a distance from a dipole in both the transverse and longitudinal direction. We did this using a Hall Effect Probe and a magnetic dipole. What I found after plotting a Log...
  40. P

    Magnetic field strength in hysteresis?

    Hi, I have been reading about magnetic hysteresis and all sources refer to magnetic field strength (H) as having the units (A/m). Why is it just amps/meter and not ampere-turns/metre as H = NI/L and not N/L? Is there another equation for H that I am unaware of? Cheers.
  41. O

    Capacitor Fringe Field Strength on Axis

    Homework Statement Show that the transformation w = e^{z} + z maps the infinite lines y = \pm\pi into semi-infinite lines u \leq u_{0}, v = \pm\pi. This is equivalent to transforming an infinite or edgeless parallel-plate capacitor (z-plane) into a parallel plate capacitor (w-plane). Sketch...
  42. A

    Superconductor: Magnetic Field Strength VS distance

    Hi all, Does anyone know how the magnetic field strength of a superconductor varies as distance from the outside of the superconductor? Aside from a superconductor being able to creates a stronger magnetic field than a regular dipole, does the strength still go down as 1/r^2 or does it...
  43. S

    Electric Field Strength Conservation in Direction of Motion

    (Sorry for the typo in the title. I don't know how to get rid of it) Recently I was looking at the Lorentz co-variance of F=dA (the Faraday 2-form) and *F=*dA (the Maxwell 2-form). I realized that Lorentz co-variance implies that the electric field strength and magnetic field strength are...
  44. M

    What is Gravitational Field Strength in General Relativity?

    "gravitational field strength" Hi all, I've been reading some lecture notes by G. t'Hooft, available from http://www.staff.science.uu.nl/~hooft101/lectures/genrel_2010.pdf On page 12, t'Hooft is discussing the Rindler space of an observer using co-ordinates \xi^{\mu} with constant...
  45. U

    Electric field strength and electrostatic potential

    1. The problem is in the attachments. 2. Field strength is equal to voltage divided by distance 3. I want to make sure that i understand a few things before i solve this problem! i would like to know your opinion! a) first, field strength is inversely proportional to the the distance squared...
  46. O

    Commutator between covariant derivative, field strength

    Hello, i try to prove that ∂μFμ\nu + ig[Aμ, Fμ\nu] = [Dμ,Fμ\nu] with the Dμ = ∂μ + igAμ but i have a problem with the term Fμ\nu∂μ ... i try to demonstrate that is nil, but i don't know if it's right... Fμ\nu∂μ \Psi = \int (∂\nuFμ\nu) (∂μ\Psi) + \int Fμ\nu∂μ∂\nu \Psi = (∂\nuFμ\nu) [\Psi ]∞∞...
  47. A

    Ferromagnetic resonance oscillating field strength

    Hello. What oscillating field strength, in tesla, is required to cause the magnetization vector of a ferromagnetic material to precess with a fairly large angle at its resonance frequency? I can't find this number anywhere!
  48. S

    Magnetic field strength in two wires

    1. Multiple choice problem, the prompt is the following: Two wires carry currents is opposite directions, as shown below. The wires are separated by a distance of 0.02 meter, and points P and Q are located 0.01 meter above and below the bottom wire. Compare the Magnetic field strength at...
  49. P

    Electromagnetism, finding magnetic field strength

    1. A 0.034 kg copper rod is hung by two wires and placed in a constant magnetic field. A current of 14 A runs through the 0.050 m long copper rod, making it hang at an angle of 34° from the vertical as attached in the diagram. What is the magnetic field strength holding the copper rod in...
  50. 4

    Question about value of the metric tensor and field strength

    Is it the value of the metric tensor that determines the strength of a gravitational field at a specific point in spacetime?
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