Exam 27: Sources of the Magnetic Field

Two long,straight parallel wires 7.6 cm apart carry currents of equal magnitude I.They attract each other with a force per unit length of 4.3 nN/m.The current I is approximately

A long solenoid is wound around a titanium core ( $\chi$ _m = 7.06 $\times$ 10^-5)and carries a current.If the core is removed while the current is held constant,the magnetic field inside the solenoid

When a sample is inserted into a solenoid carrying a constant current,the magnetic field inside the solenoid increases by 0.005%.What is the magnetic susceptibility of the sample?

A tightly wound solenoid is 15 cm long,has 350 turns,and carries a current of 3.0 A.If you ignore end effects,you will find that the value of at the center of the solenoid when there is an iron core of magnetization M = 1.4 $\times$ 10⁶ A/m is approximately

A tightly wound solenoid 15 cm long has 350 turns and carries a current of 3.0 A.If you ignore end effects,you will find that the value of at the center of the solenoid when there is no core is approximately

A point charge is moving with speed 2 $\times$ 10⁷ m/s along the x axis.At t = 0,the charge is at x = 0 m and the magnitude of the magnetic field at x = 4 m is B₀.The magnitude of the magnetic field at x = 4m when t = 0.1 $\mu$ s is

A long cylindrical bar magnet has a magnetization M = 3000 A/m.What is the equivalent current on the curved surface of the cylinder for 5 cm length of the magnet?

The two wires in a DC adapter cable are 5 mm apart and carry a current of 4 A.If the cable is 1.5 m long,calculate the force between the wires and state if this force is attractive or not.

A wire carries an electric current straight upward.What is the direction of the magnetic field due to the current north of the wire?

Two current-carrying wires are perpendicular to each other.The current in one flows vertically upward and the current in the other flows horizontally toward the east.The horizontal wire is 1 m south of the vertical wire.What is the direction of the net magnetic force on the horizontal wire?

The force per unit length between two current-carrying wires is expressed as where I is the current,d the separation of the wires,and l the length of each wire.A plot of force per unit length versus I² gives a straight line,the slope of which is

A 1000-turn solenoid is 50 cm long and has a radius of 2.0 cm.It carries a current of 8.0 A.What is the magnetic field inside the solenoid near its center?

In a simple picture of the hydrogen atom,the electron moves in circular orbits around the central proton attracted by the Coulomb force.The lowest (n = 1)energy orbit that is allowed for the electron is at a radius of 5.29 $\times$ 10^-11 m and the second (n = 2)lowest allowed orbit is at 4 times this radius.How many times stronger is the magnetic field strength at the proton due to the orbital motion of the electron in the n = 1 state than the n = 2 state?

A wire of radius 0.6 cm carries a current of 10 A that is uniformly distributed over its cross section.Calculate the magnetic field strength at r = 0.2 cm divided by that at r = 0.4 cm.

A cylindrical bar magnet of radius 0.65 cm and length 8.3 cm has a magnetic dipole moment of magnitude m = 1.4 A · m².What is the pole strength of the magnet?

A tightly wound solenoid is 15 cm long,has 350 turns,and carries a current of 3.0 A.If you ignore end effects,you will find that the value of _app at the center of the solenoid when there is no core is approximately

A long solenoid with 15 turns per centimeter has a core of annealed iron.When the current is 1.00 A,the magnetic field inside the iron core is 2.46 T.The magnetization M is approximately

A circular loop of wire of radius 6.0 cm has 30 turns and lies in the xy plane.It carries a current of 5 A in such a direction that the magnetic moment of the loop is along the x axis.The magnetic field on the x axis at x = 6.0 cm is approximately

A circular loop of wire 1.0 cm in radius carries a current of 30 A.The magnetic field at the center of the loop is

Two parallel wires carry currents I₁ and I₂ = 2I₁ in the same direction.Which of the following expressions shows the relationship of the forces on the wires?