Consider a long (practically infinite) straight wire of radius, a, carrying a steady current that is uniformly distributed over its cross section as shown in the figure. Which of the following is FALSE? Contour C₂ for r₂a (a) Cylindrical wire (b) Wire cross section Contour C₁ for ra B © The magnitude of the magnetic field intensity, H, inside the wire is proportional to the distance,,, from the wire axis. The magnitude of the magnetic field intensity, H, on the surface of the wire (ra) is inversely proportional to a². The magnitude of the magnetic field intensity, H, outside the wire is inversely proportional to the distance, r, from the wire axis. The magnitude of the magnetic field intensity, H, outside the wire is proportional to the current, 7, on the wire.

A square magnetic core has a mean length of 43 cm and a cross-sectional area of120cm2. A coil of 200 turns of wire is wound around one of the columns of the core, thewhich is made of a material whose required magnetic field strength is H=115 Aturns/m. a) How much current is required to produce a flux of 0.012 Wb, in the core?b) What is the relative permeability of the core for that current?c) What is the reluctance?

you these questions. The dimensions of a ferromagnetic core are shown in the figure below. Assuming the core is built from an ideal material with an infinite permeability, consider that the coil has 1000 turns, and the core cross-section is 250 mm². Given that the permeability of free space = 4 x 10-7 H/m, answer the following questions: a) Calculate the total reluctance of the flux path. b) Determine the magnetomotive force when the current flowing in the coil is 150 mA. c) What is the magnitude of the flux produced by a current of 10 A in the coil? d) Plot the direction of the flux in the figure, 1mm considering the direction of the current in the coil. e) Sketch the Magnetic Circuit, labeling each component with its corresponding value. 2 mm 5 mm 3 mm 3 mm 5 mm

A solenoid similar to the figure below, has a core made of caststeel (refer to the figure on the next slide). It has a cross-sectional area of 4cm2 and a mean length of 20cm. The coil has 100turns, and the coil current is 3.2A. Find the following:a)magnetomotive force, mmfb)magnetic field intensity, Hc)flux density, B (with graph)

(a) Given a magnetic circuit as shown in Figure Q3(a)(i) where the core is a cast steel. B- H curve for the cast steel is shown in Figure Q3(c)(ii). The center limb has a cross- sectional area of 600 mm² and each of the side limbs has a cross sectional area of 450 mm?. A coil of 200 turns is wound on the central limb. Neglect any magnetic leakage and fringing effect. You are required to provide the equivalent Ampere's Cireuital Law model with the detail of the labelling and also investigate the m.m.f. and current values that are required to establish a flux of 8.4 x 104 Wb in the centre limb. mm 250 mm 250 mm 100 mm Figure Q3(a)(i) B (T) 1.6 Sheet steel Cast steel 1.4 1.2 1.0 0.8 Cast iron 0.6 0.4 0.2 H(Alm) 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 Figure Q3(a)(ii) 班

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d. Find the magnitude of the magnetic field due to wire2 at the location of field point e. Find the unit directions for f and i and perform the cross product to detemine the direction of the magnetic field due tó wire2 at the location of field point P. 1. Find the magnitude of the magnetic field due to wiret at the location of field point P

A long, cylindrical wire has the cross-section of an annulus, i.e. region between twoconcentric circles, see the shaded area in figure a). The outer radius of the wire is 2R, the innerdiameter is R. Current I flows along the wire (perpendicularly into the page) in uniform distributionbetween radii R and 2R. 1)Find and plot the magnitude of the magnetic field as a function of distance r from thesymmetry axis of the wire.2) Suppose now that the cavity of radius R is not coaxial with the outer surface of the wire, asseen in figure b). Find the magnetic field at point P located in the center of the cavity. The currentdistribution in the wire is assumed to be uniform, the value of current is I.

Consider the magnetic circuit in figure. current of (3A) flows through 200 turns of wire around a core of cross sectional aea of 0.24 (m) 103 m? and a relative permeability of 5000. 2 (mm) a) Determine the magnetic flux in each leg b) Determine the magnetic field intensity in the air gap -0.2 (m) 0.2 (m) c) Determine the magnetic force on the across the air gap

A DC current I flows in a long solenoidwith n coil-turns per unit length. Thecore is made of iron with permeability µ , and has a cross section area S.Determine the force acting on the coreif it is withdrawn to the position shownin figure.