Exam 28: Magnetic Fields of Moving Charges

An ideal solenoid has a field of magnitude 0.10 T when carrying a current of 200A. The solenoid is 5.0 m long.What is the number of turns for the coils of the solenoid?

A square loop of wire,20 cm long on each side carries a current of 0.3 A.What is the magnetic field in the center of the square loop?

Two long wires lie parallel to the x-axis;one at y = 0.0 m,the other at y = 0.12 m.The first carries current of 1.0 A in the positive x direction,while the other carries current of 1.5 A in the negative x direction.Which of the below is a y-coordinate value at which there is no magnetic field?

In a solenoid magnet in which the wires are wound such that each winding touches the previous,which of the following will increase the magnetic field inside the magnet?

Proton A travels northward with a constant velocity.Due north of proton A is proton B,traveling to the east at a different constant velocity.In what direction is the magnetic force on B?

Each of two long straight parallel wires separated by a distance of 24.0 cm carries a current in the same direction.If the resulting magnetic field at a point that is 14.0 cm from each wire is 12.8 µT,what is the current flowing through one of the wires?

The overhead cable for a street trolley is strung horizontally 5 m above the ground.A long straight section of it carries a 100 A current due west.What is the magnetic field due to the current in the cable at street level directly under the cable?

An electron is shot from an electron gun with a speed parallel to and a distance of 2.0 cm above a long straight wire carrying a current of 10A. The magnitude of its acceleration at the instant it leaves the electron gun is 6.1 * 10¹¹ m/s .What is the speed of the electron.

Two wires carry different currents in the opposite directions as shown.Where is it possible for the magnetic field produced by the wires to be zero?

A long solenoid (diameter = 4.00 cm)is wound with 1500 turns per meter of thin wire through which a current of 0.220 A is maintained.A wire carrying 5.00 A is inserted along the axis of the solenoid.What is the magnitude of the magnetic field at a point 1.00 cm from the axis?

In a coaxial cable,the solid inner conductor carries a current of I.The shield,which also carries a current of I but in the opposite direction,has an inner radius of a and an outer radius of b.The current density is equally distributed over each conductor.What is the magnitude of at a radial distance of 1.05 mm from the center of the coaxial cable if a = 1 mm,b = 1.1 mm and I = 100 mA?

A long solenoid (diameter = 5.00 cm)is wound with thin wire through which a constant 0.292 A current is maintained.A wire carrying an 8.5 A current is inserted along the axis of the solenoid.The magnitude of the magnetic field at a point 5.00 mm from the axis is 0.650 mT.What are the number of turns per unit length for this solenoid?

Wire 1 has a semicircular section of radius R followed by a straight section of length R as shown in the figure,and carries a current I₁.Wire 2,which is perpendicular to the page,carries a current I₂,where I₂ flows out of the page.If R is doubled,by what factor will the magnitude of the magnetic force on wire 1 due to the magnetic field created by wire 2 change?

Two long wires are suspended by 16-cm long threads attached from the ceiling so that they are parallel to each other and to the ceiling above.They each carry an electric current of 15A,in opposite directions.When they carry no current,the wires hang such that they are touching all along their length,and the threads are vertical and immediately adjacent to one another.If the angle between the threads is 10.0 ^$\circ$ ,what is the mass per unit length of the wires?

The current in a wire is uniformly distributed over the cross-sectional area of the wire.The radius of the wire is r.Where is the magnitude of the magnetic field generated by the current flowing through the wire greatest?

A wire of radius R = 4 mm carries a uniformly distributed current of 2 A.The magnetic field inside the wire at a radial distance R/2 from the axis of the wire is

A square,clamping ammeter has four sides each with a length of 3.0 cm.The four sides of the ammeter are capable of measuring the magnetic field at the position of the sides.When the ammeter is clamped around a cylindrical wire carrying a DC current as shown in the figure,the average magnetic field measured in the sides of the clamp is 2.0

Find the magnitude of the magnetic force on a wire,which has semicircular section of radius R followed by a straight section of length R as shown in the figure,carrying a current I₁= 10 A,due to the magnetic field created by a second wire,which is perpendicular to the page,carrying a current I₂ = 10 A.I₂ flows out of the page and R = 10 cm.

A large 1 m by 1 m sheet conductor in the x-y plane carries a uniform current flowing in the x-direction.The current density is 1.7 A/cm.What is the direction of the magnetic field just above the center of the sheet at z = 2 mm (not close to any edges).

Two wires,A and B,are parallel to each other and separated by a distance of 30 cm.Wire A carries a current of 1.2 A in one direction while wire B carries a current of 3.1 A in the opposite direction.Where is the magnetic field equal to zero?