Exam 30: Sources of the Magnetic Field

Equal currents of magnitude I travel out of the page in wires M and N.Eight directions are indicated by letters A through H. The direction of the magnetic field at point P is

Two long straight wires carry currents perpendicular to the xy plane.One carries a current of 50 A and passes through the point x = 5.0 cm on the x axis.The second wire has a current of 80 A and passes through the point y = 4.0 cm on the y axis.What is the magnitude of the resulting magnetic field at the origin?

A long solenoid (n = 1200 turns/m,radius = 2.0 cm)has a current of a 0.30 A in its winding.A long wire carrying a current of 20 A is parallel to and 1.0 cm from the axis of the solenoid.What is the magnitude of the resulting magnetic field at a point on the axis of the solenoid?

Two long parallel wires each carry a current of 5.0 A directed to the east.The two wires are separated by 8.0 cm.What is the magnitude of the magnetic field at a point that is 5.0 cm from each of the wires?

The magnetic field at (+3 m,0,0)is in the negative y direction.

A conducting hollow cylinder (inner radius = a,outer radius = b)carries a current of 40 A that is uniformly distributed over the cross section of the conductor.If a = 3.0 mm and b = 6.0 mm,what is the magnitude of the (line)integral Around a circular path (radius = 5.0 mm)centered on the axis of the cylinder and in a plane perpendicular to that axis?

A long solenoid (1000 turns/m)carries a current of 25 mA and has an inside radius of 2.0 cm.A long wire which is parallel to and 4.0 cm from the axis of the solenoid carries a current of 6.0 A.What is the magnitude of the magnetic field at a point on the axis of the solenoid?

We find that N current loops are coplanar and coaxial.The first has radius a and current I.The second has radius 2a and current 2I,and the pattern is repeated up to the Nth,which has radius Na and current NI.The current in each loop is counterclockwise as seen from above.The magnitude of the magnetic field at the center of the loops is

A solenoid 4.0 cm in radius and 4.0 m in length has 8 000 uniformly spaced turns and carries a current of 5.0 A.Consider a plane circular surface (radius = 2.0 cm)located at the center of the solenoid with its axis coincident with the axis of the solenoid.What is the magnetic flux through this surface? (1 Wb = 1 T ⋅ m²)

A hollow cylindrical (inner radius = 1.0 mm,outer radius = 3.0 mm)conductor carries a current of 80 A parallel to its axis.This current is uniformly distributed over a cross section of the conductor.Determine the magnitude of the magnetic field at a point that is 2.0 mm from the axis of the conductor.

The figure shows a cross section of three parallel wires each carrying a current of 20 A.The currents in wires A and B are out of the paper,while that in wire C is into the paper.If the distance R = 5.0 mm,what is the magnitude of the force on a 2.0-m length of wire A?

A long,straight wire (radius = 2.0 mm)carries a current of 2.0 A distributed uniformly over a cross section perpendicular to the axis of the wire.What is the magnitude of the magnetic field at a distance of 1.0 mm from the axis of the wire?

A straight wire (length = 8.0 m)is bent to form a square.If the wire carries a current of 20 A,what is the magnitude of the magnetic field at the center of the square?

Two solenoids of equal length are each made of 2000 turns of copper wire per meter.Solenoid I has a 5.00 cm radius;solenoid II a 10.0 cm radius.When equal currents are present in the two solenoids,the ratio of the magnitude of the magnetic field B_I along the axis of solenoid I to the magnitude of the magnetic field B_II along the axis of solenoid II,B_I/B_II,is

The figure shows a cross section of three parallel wires each carrying a current of 5.0 A out of the paper.If the distance R = 6.0 mm,what is the magnitude of the magnetic force on a 2.0-m length of any one of the wires?

Three coplanar parallel straight wires carry equal currents I to the right as shown below.Each pair of wires is a distance a apart.The direction of the magnetic force on the middle wire

Two current loops are coaxial and coplanar.One has radius a and the other has radius 2a.Current 2I in the outer loop is parallel to current I in the inner loop.The magnitude of the magnetic field at the center of the two loops is

A superconducting wire carries a current of 1.0 × 10⁴ A.Find the magnetic field at a distance of 1.0 m from the wire.

The magnetic moment of an electron (charge = −e;mass = m_e)moving in a circular orbit of radius r with speed v about a nucleus of mass m_N is proportional to

On the average,in a ferromagnetic domain permanent atomic magnetic moments are aligned ____ to one another.