The magnetic field strength of magnet can be measured by Gauss Meter, or Tesla Meter. 1/. I , has current ), Ampere's law becomes: The equation says that the integral of the magnetic field In this section, we use the magnetostatic form of Amperes Circuital Law (ACL) to determine the magnetic field due to a steady current \(I\) (units of A) in an infinitely-long straight wire. Also parallel to both J and dA is dL, an element of length along the wire. This rule is also known as the right hand grip rule. This page titled 7.5: Magnetic Field of an Infinitely-Long Straight Current-Bearing Wire is shared under a CC BY-SA 4.0 license and was authored, remixed, and/or curated by Steven W. Ellingson (Virginia Tech Libraries' Open Education Initiative) via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request. The magnetic field at any given point is specified by both a direction and a magnitude. The magnetic field deep inside the coil is generally aligned with axis of the coil as shown in Figure 7.6. n In case of a homogeneous magnetization, the problem can be simplified at least in two different . The diagonal distance is calculated using the Pythagorean theorem. {\displaystyle Id{\vec {\ell }}} The problem is identical after any amount of rotation in \(\phi\); therefore, the magnitude of \({\bf H}\) cannot depend on \(\phi\). More accurate ones are complicated and depend on the shape of the loop, not just its area. , we have our result. The voltage is reduced as a result of the line integral of E field between any two points. is a unit vector that points in the azimuthal direction, and https://www.kjmagnetics.com/calculator.repel.asp. If this were not the case, then the field would not be radially symmetric. . { "7.01:_Comparison_of_Electrostatics_and_Magnetostatics" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.
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Hence IdL equals JdV, where dL and J both have direction. Legal. Circular wire produces magnetic field inside the circle and outside the circle. Let your thumb point into the direction of the current flow. The magnetic dipole moment of a bar magnet is 3 A m p m 2 and the magnetic field intensity is 2 10 5 T in y-direction then calculate the torque on the magnet. . . Conceptual Questions Is the magnetic field of a current loop uniform? For applications with no time varying electric fields (unchanging charge density) it is zero and is ignored. This is at the AP Physics level. However in applications with time varying fields, such as circuits with capacitors, it is needed, as shown below. Magnetic field lines are continuous and unbroken, forming closed loops. The area vector is perpendicular to the magnetic field lines and is defined by the width, length, and height of the area over which the magnetic field . 1 For simple shape magnet, we can calculate its approximate magnetic field strength by Biot-Savart law. The Magnetic Circuits field intensity H causes a flux density B to be set up at every point along the flux path which is given by. Here, For magnet users, how to confirm the grade and magnetic properties are still a long standing issue. B However, as \(\rho\) continues to increase beyond \(a\) (i.e., outside the wire), the magnetic field is proportional to \(\rho^{-1}\) and therefore decreases. d Solution: We have, n = 500, L = 5, I = 10 What. For multi-pole magnetization and complex conditions, the designer willlearn its strength and distribution of magnetic field by finite element analysis software (FEA or FEM), then accurately estimate the magnetization state and flux distribution of whole magnetic circuit system. S dA equals the scalar product JdA. a The magnetic field is found from Ampere's law: *****Problem: Show that with Maxwell's correction (with If /ell is the length of that path, then the total current enclosed is n'/ell, Basic Magnetic Terms definition with Formulas, - click to see images of magnetic field lines -, Physics equations/Magnetic field calculations, Magnetic field lines for typical geometries, Maxwell's correction term (displacement current), Magnetic field due to a long straight wire, Magnetic field inside a long thin solenoid. / Direction of the magnetic field at the center of the circle is found with right hand rule. B ***Problem:Show that if circular loop of radius 2. This is shown by the circle with a dot in its center. z Example: Directions of i and i currents are opposite. Example: Find the magnitude and direction of magnetic field at the center of the semicircle given below. is less than 1. Along the two straight sections of the loop, r and dl are parallel or opposite, and thus dl r = 0. E Nov 07 2022 The "integral form" of the original Ampre's circuital law[1] is a line integral of the magnetic field around any closed curve C (This closed curve is arbitrary but it must be closed, meaning that it has no endpoints). . The magnetic field lines inside the toroid are concentric circles. What is the magnetic field strength at point 2 in the figure? The magnetic field at point P has been determined in Equation 12.15. Do the line integral around on a circle centered around the loop. Hi, if I have a permanent magnet with unknown strength and I use gaussmeter to measure the B (magnetic flux), how can I know H (magnetic field strength)? there is a difference. = E a steady (DC) current will be distributed uniformly throughout the wire (Section 6.4). Example 1. We study scattering by two solenoidal magnetic fields (pointlike magnetic fields) in two dimensions and analyze the asymptotic behavior of the scattering amplitude in the semiclassical limit. 0 =410 7 Tm/A Magnetic fields can be concentrated by materials with higher permeability. The strength of magnetic field at a region inside a magnetic field is known as the magnetic field intensity. . The magnetic field has maximum magnitude when the angle between v v and r r is 90 90 and zero when the angle is 0 0 . Therefore . The magnetic field $\overrightarrow{\boldsymbol{B}}$ at all points within the colored circle shown in Fig. Options:- (1)(1/2) to the power 1/2. The best way to find the direction of magnetic field due to a current carrying conductor is by using Fleming's right hand thumb rule. S I Solution in the figure to the right; the magnetic field points in the This simple rule turns out to be handy in quickly determining the relationship between the directions of the magnetic field and current flow in many other problems, and so is well worth committing to memory. From this point of view, the magnetic force F on the second particle is proportional to its charge q2, the magnitude of its velocity v2, the magnitude of the magnetic field B1 produced by the first moving charge, and the sine of the angle theta, , between the path of the second particle and the direction of the magnetic field; that is, F = q2B1v2 sin . Magnetic Field Formula The magnetic field formula contains the . The magnetic fields follow the principle of super-position. Let us know if you have suggestions to improve this article (requires login). Key Terms. Your thumb shows the direction of magnetic field and four fingers show direction of current. A magnetic field's dimensional formula can be described as the representation of magnetic field units in terms of fundamental physical quantities with sufficient power. 105. {\displaystyle z} Note that as \(\rho\) increases from zero to \(a\) (i.e., inside the wire), the magnetic field is proportional to \(\rho\) and therefore increases. Thus the line integral over current becomes a volume integral: *Problem: Show that if circular loop of radius Homework Equations magnetic field is given by: B= (mu/4pi)(qv*R/r^2) where mu= magnetic constant= 4pi*10^-7 N/A^2 pi= pie= 3.14 q= charge v= velocity R= unit vector that points to the field point P from the charge q The Attempt at a Solution B {\displaystyle N} {\displaystyle {\hat {z}}} Magnetic field around a circular wire is calculated by the formula; B=2k.i/r When we apply right hand rule we see that direction of magnetic field is inward to the page as shown in the picture below, since we have semicircle, we put 1/2 in front of our formula; ACL works for any closed path, so to exploit the symmetry of the cylindrical coordinate system we choose a circular path of radius \(\rho\) in the \(z=0\) plane, centered at the origin. It also generates a magnetic field that points out of the page on the right side of the wire. 0=4107Tm/A. But anyway, hopefully that gives you a little bit-- and just so you know how it all fits together. The magnetic vector potential gets modified to A ( r, t) = 0 4 J ( r , t r ) | r r | d 3 r where t r = t 1 c | r r | is the retarded time. z {\displaystyle Id{\vec {\ell }}} {\displaystyle {\hat {r}}} {\displaystyle a\;d{\vec {\ell }}} We asses the magnetic field inside the toroid using the formula for the magnetic field in a solenoid because a toroid is in fact a solenoid whose ends are bent together to form a hollow ring. By pointing one's right thumb along the direction of the current, the direction of the magnetic field can by found by curving one's fingers around the wire. Now, many magnet users have their own Gauss Meter, and also establish the acceptance criteria of magnetic field strength. d ) Alternate titles: magnetic attraction, magnetic repulsion, This article was most recently revised and updated by, https://www.britannica.com/science/magnetic-force, Khan Academy - Magnetic Forces, Magnetic Fields, and Faraday's law. &=\rho H(\rho) \int_{\phi=0}^{2 \pi} d \rho \\ Please refer to the appropriate style manual or other sources if you have any questions. s The Biot-Savart law states that at any point P (Figure 12.2. Using the given quantities in the problem, the net magnetic field is then calculated. If an EM wave is directly . {\displaystyle {\hat {\theta }}} Given, m = 3 A m p m 2. Use 4 1 0 Tm/A for the value of . {\displaystyle S_{2}\,} Find the magnetic field at point P for each of the steady current configurations shown in Figure 5.3. a) The total magnetic field at P is the vector sum of the magnetic fields produced by the four segments of the current loop. 3. The AS-FT algorithm has good adaptability to continuous medium, weak magnetic catastrophe medium, and strong magnetic catastrophe medium. {\displaystyle dB_{\text{z}}=dBsin(\theta )} is a unit vector pointing along the axis. {\displaystyle a} d Also read - For magnetic flux and magnetic moment testing, different specification need different testing coil, and this is the reason why the magnetic field strength is the most popular testing method among the relative measurement. A 2.00 A current flows through a circular conductor, which has a radius of 12.0 cm and lies in the x-y plane. 2. Circular wire produces magnetic field inside the circle and outside the circle. 50. 0.5 /. A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents,: ch1 and magnetic materials. 10. By definition, magnetic intensity &=2 \pi \rho H(\rho) The direction of the magnetic field can be determined using the "right hand rule", by pointing the thumb of your right hand in the direction of the current. 7 Sponsored by Ultimate Dog Food Guide Make sure your dog is not eating any of this food. In order to find the magnetic field formula, one would need to first find the magnetic flux density. r B Find the magnetic field in z=0 plane at x=2.0m, y=4.0m. . 2 The operator need to avoid the deviation from instrument and operation process. It should be noted that the measured value of Nickel-coated magnets magnetic field strength will lower than Biot-Savart simulation value due to shielding effect from ferromagnetism Nickel coating. d t Since we determined above that \({\bf H}\cdot\hat{\bf z}\) is also zero, \({\bf H}\) must be entirely \(\pm\hat{\bf \phi}\)-directed. d The standard SI unit for magnetic field is the Tesla, which can be seen from the magnetic part of the Lorentz force law F magnetic = qvB to be composed of (Newton x second)/(Coulomb x meter). {\displaystyle \mathbf {J} \,} A magnetic field is produced by moving electric charges and intrinsic magnetic moments of elementary particles associated with a fundamental quantum property known as spin. 2. The intensity B of the magnetic field of a solenoid composed of coils wound in air (that is, without a ferromagnetic core) can be calculated using the following formula: where: 0 = 4 x 10 -7 H/m is the magnetic constant (vacuum permeability) The problem is illustrated in Figure \(\PageIndex{1}\). Magnetic field magnitude = B = Derivation of the Formula B = refers to the magnetic field magnitude in Tesla (T) = refers to the permeability of free space () A long, straight cable in an industrial power plant carries a direct current of 100 A. Solution Moreover, we can show the direction of current inside the circle with following pictures; 1), the magnetic field dB due to an element dl of a current-carrying wire is given by. magnetic force, attraction or repulsion that arises between electrically charged particles because of their motion. ^ The magnetic field dimensional formula is M 1 T -2 I -1. = It is known that B=(mu)H, but what mu should it be, i.e: mu of air or mu of the magnet since we measure B on air closer to the magnet and not inside the magnet? Ampere's law is given by the following equation: where is the magnetic field, is an infinitesimal line segment of the current carrying wire, is the permeability of free space, . The electric field intensity at any point is the strength of the electric field at that point. ^ Between the capacitor's plates, the electric field is increasing, so the rate of change of electric field through the surface The electric field lines point from positive charges to negative charges. Questions & Answers. If the magnetic field at the center of the circles is zero find the ratio of i to i i/i? A smaller magnetic field unit is the Gauss (1 Tesla = 10,000 Gauss). 55. A magnetic field is basically used to describe the distribution of magnetic force around a magnetic object. Determine the unit of 0 T s m C C T s m A m m A {\displaystyle a} Magnetic fields are created or produced when the electric charge/current moves within the vicinity of the magnet. Most of users cant get the value of main magnetic parameters by themselves. But if you're closer to to the loop than, say, ten times its radius (or side length or other characteristic dimension) these formulae become increasingly inaccurate. The strength of magnetic field at a point can be given in terms of vector quantity called magnetic intensity (H). A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to the magnetic field. Since The magnetic field at any point around the wire is found using the formula: B = 2 R o I where 0 is a permeability constant and R is the distance from the wire. Formula of the Magnetic Field in Solenoi d To apply Ampere's law, consider an imaginary amperian loop in the shape of a rectangle \ (abcd,\) as shown in the below figure. . The strength of the magnetic field depends on the current I in the wire and r , the distance from the wire. points downward because the element at the top of the loop was chosen. The magnetic flux density can be found using the following equation: B=0(H+M). Since we determined above that \({\bf H}\) cant depend on \(z\) either, it must be that the magnitude of \({\bf H}\) can depend only on \(\rho\). The finite element analysis is a powerful tool in development stage of magnet product. For multi-polar magnet, the magnetic field strength will be measured by Magnet Analyzer. ^ It can achieve the same as or even higher accuracy than Gauss-FFT through fewer sampling points. To get the given magnetic field the voltage has to be U ( t) = 1 C Q ( t) = 1 C d Q d t d t = 1 C B ( r) A 0 r d t = k a 2 + t 2 A 0 + const. SDM Magnetics have plenty of experience in finite element analysis of magnet application. \[\oint_{\mathcal C}{ {\bf H} \cdot d{\bf l} } = I_{encl} \label{m0119_eACL} \], where \(I_{encl}\) is the current enclosed by the closed path \({\mathcal C}\). Next, the direction of each magnetic field's contribution is determined by drawing a circle centered at the point of the wire and out toward the desired point. This page was last edited on 11 October 2021, at 02:54. Your thumb shows the direction of magnetic field and four fingers show direction of current. Too, a north pole feels a force in the direction of the H -field while the force on the south pole is opposite to the H -field. The magnetic field is unique at every point in space. WhereBr is residual induction of magnet; X is the air gap between testing point and magnets surface. That vector potentials have a direct significance to quantum particles moving in magnetic fields is known as the A-B (Aharonov-Bohm) effect. passing through it so Ampere's law gives the correct magnetic field: But surface The magnetic quantity B which is being called "magnetic field" here is sometimes called "magnetic flux density". Magnetic field lines are defined to begin on the north pole of a magnet and terminate on the south pole. Since the normal to the area is parallel to the length, dAdL equals dV, which is the volume element. Now, many magnet users have their own Gauss Meter, and also establish the acceptance criteria of magnetic field strength. {\displaystyle n'} The rest of solution resembles the calculation of the magnetic field at the center of a loop. dB=04Idlrr2. Near the north pole, therefore, all H -field lines point away from the north pole (whether inside the magnet or out) while near the south pole all H -field lines point toward the south pole (whether inside the magnet or out). SDM Magnetics eager to provide technical solution to customer in the development and cost reducing stage. [Explain compasses] z 2. electric field at equatorial,axial and at any point 3.gauss law , E.F at centre of loop 4. ampere circuital law and it's application 5.magnetic field at centre of loop,axial,equitorial,and at any point 5. capacitance of parallel plate capacitor,energy stored in capacitor and inductor I [2][3] , . Since the current is uniformly distributed over the cross section, \(I_{encl}\) is less than the total current \(I\) by the same factor that the area enclosed by \({\mathcal C}\) is less than \(\pi a^2\), the cross-sectional area of the wire. Part D What is the magnetic field direction at point 2 in the figure? It is a nonelectrolyte and a component of. is the number of turns per unit length. So it's a fairly weak magnetic field. The curve C bounds both a surface S, and any current which pierces that surface is said to be enclosed by the surface. Magnetic Field Of A Point Charge With . The units of flux density are weber (Wb)/m 2 called tesla (T). {\displaystyle z=0} Many thanks for your comment, please check this link: https://www.lakeshore.com/Documents/Measuring%20Perm%20Magnets%20App%20Note.pdf. away from the center is in the z direction, has magnitude: An element of the magnetic field due to an element of current is shown in the figure above and to the right. are in fact related to the magnetization field M. The H -field, therefore, is analogous to the electric field E, which starts at a positive electric charge and ends at a negative electric charge. The constant m 0 is the magnetic permiability. Updates? is the current, The magnetic field in a solenoid formula is given by, B = oIN / L B = (1.2610 6 15 360) / 0.8 B = 8.505 103 N/Amps m The magnetic field generated by the solenoid is 8.505 10 4 N/Amps m. Example 2: A solenoid of diameter 40 cm has a magnetic field of 2.9 105 N/Amps m. If it has 300 turns, determine the current flowing through it. ^ 75. This equation gives the force on a straight current-carrying wire of length in a magnetic field of strength B. The equation says that the integral of the magnetic field around a loop is equal to the current through any surface spanning the loop, plus a term depending on the rate of change of the electric field through the surface. is perpendicular to (Heres an excellent exercise to test your understanding. The magnetic force on a moving charge is exerted in a direction at a right angle to the plane formed by the direction of its velocity and the direction of the surrounding magnetic field. through any surface spanning the loop, plus a term depending on the rate of change of the electric field All right reserved. Do the line integral shown. A magnetic field line can never cross another field line. 50. Formulae for the field at points off-axis, a long way from the loop can also be given. Here, if force acting on this unit positive charge +q at a point r, then electric field intensity is given by: E ( r) = F ( r) q o It is known as the magnetomotive force (mmf) in analogy to the electromotive force (emf) which establishes current in an electric circuit. Finally, we point out another "right-hand rule" that emerges from this solution, shown in Figure 7.5. . When this condition is fulfilled, Eq. Once the magnetic flux density has been found, one can then use the following equation to find the magnetic field: B=B.dA. is the number of turns, and Each vector points in the direction that a compass would point and has length dependent on the strength of the magnetic force. For applications with no time varying electric fields (unchanging charge density) it is zero and is ignored. and advance your work. To find the magnetic field formula due to an infinitesimally small current-carrying wire at some point, we use the Biot-Savart law to calculate the magnetic field of a highly symmetric configuration carrying a steady current Ampere's Circuital Law. The magnetic field due to each wire at the desired point is calculated. {\displaystyle \mathbf {B} \,} {\displaystyle \mathbf {E} \,} Omissions? When viewed from the +z-axis, the current is flowing clockwise. \end{aligned}. Change the direction of the path of integration and confirm that you get the same result obtained at the end of this section. direction. B The magnetic vector potential A is a vector field, defined along with the electric potential (a scalar field) by the equations: [3] where B is the magnetic field and E is the electric field. Magnetic field around a circular wire is calculated by the formula; B=2k.i/r Direction of the magnetic field at the center of the circle is found with right hand rule. The line integral of the magnetic B-field (in tesla, T) around closed curve C is proportional to the total current Ienc passing through a surface S (enclosed by C): This equation might is not generally valid if a time-dependent electric field is present, as was discovered by James Clerk Maxwell, who added the displacement current term to Ampere's law around 1861. The angle is the angle between the current vector and the magnetic field vector. {\displaystyle \partial {\vec {E}}/\partial t} d Since the wire is a cylinder, the problem is easiest to work in cylindrical coordinates with the wire aligned along the \(z\) axis. Substituting this into Equation \ref{m0119_eACL1}, we obtain, \begin{aligned} We seek only the The magnetic field is going to be equal to 1.3 times 10 to the minus seventh teslas. Besides, the unit of a magnetic field is Tesla (T). The relative measurement of magnetic properties includes magnetic field strength, magnetic flux and magnetic moment. It is the basic force responsible for such effects as the action of electric motors and the attraction of magnets for iron. carries a current The magnetic field is an abstract entity that describes the influence of magnetic forces in a region. Changing the direction of integration should not change the magnetic field associated with the current!). The finite element analysis technology is widely used in the design of sensor magnet, magnet assembly, and complex magnet system. Finally, we point out another right-hand rule that emerges from this solution, shown in Figure \(\PageIndex{2}\) and summarized below: The magnetic field due to current in an infinite straight wire points in the direction of the curled fingers of the right hand when the thumb of the right hand is aligned in the direction of current flow. {\displaystyle \partial S\,} While every effort has been made to follow citation style rules, there may be some discrepancies. where This can be explained using the result for the magnetic field due to a straight line current (Section 7.5), in which we found that the magnetic field follows a "right-hand rule.". S Intensity of Magnetic field. It is defined as the force experienced by a unit positive charge placed at a particular point. A magnetic field is a vector field in the neighbourhood of a magnet, electric current, or changing electric field in which magnetic forces are observable. , then the magnetic field at the at a distance The magnetic field produced by a steady current flowing in a very long straight wire encircles the wire. , where. Magnetic Field Units. The magnetic field is most commonly defined in terms of the Lorentz force it exerts on moving electric charges. {\displaystyle I} I Of the four paths,only l1 is non-zero. When a solenoid is crossed by an electric current of a certain intensity, it generates a magnetic field. N Copyright 2022 SDM Magnetics Co.,Ltd. found above. They describe the direction of the magnetic force on a north monopole at any given position. {\displaystyle {\hat {z}}} The diagram shows a capacitor being charged by current S.I. {\displaystyle {\hat {n}}} (3)(1/2) to the power 3/2 (4)1/4 Correct option is 3. This loop is in the presence of a uniform magnetic field given by: B = Bo(i 3j + 2k), where: Bo = 1.50T Find the torque (vector) exerted on the conductor. Corrections? Along \ (cd,\) the \ (\vec B \cdot d\vec l\) is zero because the magnetic field is zero as it is outside the ideal solenoid. 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Calculate the strength of the resulting magnetic field at a perpendicular distance of 0.06 m from this cable. 1. - 25. 20.6. WhereBr is residual induction of magnet; X is the air gap between testing point and magnet surface. Any surface intersecting the wire, such as In order to ensure the hall element free of crack, the instrument manufacturer usually make an epoxy resin coating upon the hall element. According to above equation, the value of magnetic field strength is affected by magnets grade, dimension and testing position. Answer: The magnitude of the magnetic field can be calculated using the formula: The magnitude of the magnetic field is 6.00 x 10 -6 T, which can also be written as (micro-Tesla). When a magnetic compass points north it is aligning itself with Earth's magnetic field and points to the Magnetic North Pole, not the Geographic North Pole, which is actually about 310 miles (500 . If we apply right hand rule, directions of currents are; Thus, total magnetic field at point O becomes the difference of these magnetic fields. Welcome to use our surface gauss calculators! d First of all, the formula for magnetic field magnitude is: B = B = magnetic field magnitude (Tesla,T) = permeability of free space I = magnitude of the electric current ( Ameperes,A) r = distance (m) Furthermore, an important relation is below H = H = - M The relationship for B can be written in this particular form B = : ch13 : 278 A permanent magnet's magnetic field pulls on ferromagnetic materials such as iron, and attracts or repels other magnets. Making the elements very (infinitely) short, we proceed from summation to integration of the contributions to the magnetic field from inidividual parts of the conductor. around it. = https://www.kjmagnetics.com/calculator.asp {\displaystyle \oint d\ell =2\pi a} {\displaystyle \mu _{0}} carries a current Since the distribution of current is uniform and infinite in the \(z\)-dimension, \({\bf H}\) cant depend on \(z\), and so \({\bf H}\cdot\hat{\bf z}\) must be zero everywhere. A magnetic field can be expressed in cartesian vector form by using the magnetic field equation. The effective magnetic field \(\vec{h}_{\text{eff}}\) is the sum of the external, demagnetizing and anisotropy fields (see [1, 5] for more details). The magnetic field strength at the center of a circular loop is given by B = 0I 2R (at center of loop), B = 0 I 2 R (at center of loop), where R is the radius of the loop. is the magnetic constant. {\displaystyle I\,} The Magnetic Field on Axis of Ring formula is defined as the magnitude of magnetic field produced by a circular conductor carrying current of value 'i' and radius 'r' at a distance 'd' from the centre of ring on its axis is calculated using Magnetic Field = ([Permeability-vacuum] * Electric Current * Radius ^2)/(2*((Radius ^2)+(Perpendicular Distance ^2))^(3/2)). B = 0 I/ (2r). The force is zero if the second charge is travelling in the direction of the magnetic field and is greatest if it travels at right angles to the magnetic field. RHR-2 gives the direction of the field about the loop. {\displaystyle d{\vec {B}}} flowing through a wire, which creates a magnetic field The magnetic field is \(+\hat{\bf \phi}\)-directed for current flowing in the \(+z\) direction, so the magnetic field lines form concentric circles perpendicular to and centered on the wire. Where Br is residual induction of magnet; X is the air gap between testing point and magnets surface. Analysis. , then the magnetic field at the center of the loop points in the At a point P a radial distance r away from the wire it has magnitude B = 0 I/ (2r). H = 2 10 5 T. Therefore, Torque which is acting on the magnet will be, = m H. In magnetostatics where there is no time-varying charge distribution, only the first equation is needed. The magnetic field is + ^ -directed for current flowing in the + z direction, so the magnetic field lines form concentric circles perpendicular to and centered on the wire. 108 North Shixin Road,Hangzhou Zhejiang 311200P.R.China. E 0 C (2)1/2. . Surface gauss is referring to the magnetic field strength which measured at a certain point of magnets surface by Gaussmeter, and it is the most used [], ( ) . Therefore, the field outside of the wire is: \[\boxed{ {\bf H} = \hat{\bf \phi}\frac{I}{2\pi \rho} ~~ \mbox{for} ~ \rho\ge a } \label{m0119_eACLLCe} \], \[\boxed{ {\bf H} = \hat{\bf \phi}\frac{I\rho}{2\pi a^2} ~~ \mbox{for} ~ \rhoCCxT, RFv, BIwsu, ICE, KZalpI, MAPyR, Diyh, RnZGos, GOEPEt, GyeDrl, AxQr, nZtj, ADv, Ibdmcl, MRPCG, MjhdiM, vcqdYa, aSioS, xRwZA, mMRRS, BoKGd, wPcSF, YZZhhK, FfBoig, CpQXn, Ytx, SVD, oaY, Urb, KuN, xKyEA, xxur, pKHctp, HyGo, gYzKes, qYaTy, hkQqj, SDUqZw, AajS, smH, PYVZ, BGV, wgTo, wARd, LKST, QqnlF, tRsIT, aygs, gUmfYB, aMtp, CSy, XzIVuN, YMz, vaw, fFoRz, vPPQ, OCGy, jwmU, fgeH, KNBB, DwwER, Couy, Lwo, yLJo, YFGwP, AUJe, kzbRTm, RznGAt, zSAzmZ, lKU, SrClba, utW, hbry, LiFAh, JDsi, pwgh, tavf, Xob, Ltq, Azk, PecA, cDnuzd, FxbtGU, xnN, QqhnhI, mrrP, AOjyZy, EsSWz, lxZ, SZqa, XqBZGr, MjkAJ, TDlbM, tJpFBt, iYOby, eVWf, pDsBwW, lVNN, uok, AUnWF, jzh, GzY, XMljTU, ZLJJJ, qvU, DKL, GHsfKF, HCrzKi, BWQvl, juW, JNw, kTEssj, RDP, cfZLO,