Exam 7: Sources of the Magnetic Field

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

If m = m_B in a paramagnetic material (m_B = 9.27 *10^-24 J/T), at what temperature is the magnetization 2% of the saturation magnetization in an applied magnetic field of 1)50 T?

Two long, straight parallel wires 9.3 cm apart carry currents of equal magnitude I. They repel each other with a force per unit length of 5.8 nN/m. The current I is approximately

Use the following figure to answer the next problem: -The tightly wound toroid shown consists of 100 turns of wire, each carrying a current I = 3 A. If a = 12 cm and b = 15 cm, the magnetic field at r = 10 cm, due to the current in this toroid, is (µ₀ = 4 $\pi$ * 10^-7 N/A²)

In a circular loop of wire lying on a horizontal floor, the current is constant and, to a person looking downward, has a clockwise direction. The accompanying magnetic field at the center of the circle is directed

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?

The graph that best represents the magnetic field on the axis inside a solenoid as a function of position x on the axis is

If m = m_B (in a paramagnetic material) for an external magnetic field of 6 T, what fraction of the saturation magnetization is M at 300 K?

The sketch shows a circular coil in the xz plane carrying a current I. The direction of the magnetic field at point O is

The magnetic field due to the presence of a charged body

A long solenoid with 20 turns per centimeter has a core of iron-silicon. When the current is 1.50 A, the magnetic field inside the core is 4.50 T. The magnetization M is approximately

A long solenoid with 20 turns per centimeter has a core of iron-silicon. When the current is 1.50 A, the magnetic field inside the core is 4.50 T. The relative permeability K_m is approximately

At great axial distances x from a current-carrying loop the magnetic field varies as

The electron orbiting a proton in a hydrogen atom has a speed of v = 2.19 F*10⁶ m/s. The magnetic moment of the electron when it is orbiting at the Bohr's radius (= 0.529 nm) is

A long straight wire of radius R carries a current density J = kr A/m² where k is a constant. The magnetic field for r > R is (Hint: Current enclosed .)

A wire of radius 0.35 cm carries a current of 75 A that is uniformly distributed over its cross-sectional area. The magnetic field at the surface of the wire is approximately

What is the direction of the magnetic field around a wire carrying a current perpendicularly into this page?

Use the following to answer the next question: -A coil of radius R = 5 cm lies inside a long solenoid which carries a current I₁ = 10 A and has 800 turns/m. The coil carries a current I₂ = 4 A and the normal of the plane of the coil is at an angle $\theta$ = 30 $\degree$ with the axis of the solenoid. The magnetic field produced by the solenoid at the center is ____ times greater than the magnetic field by the coil at the 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*10^-11 m and the second (n = 2) lowest allowed orbit is at 4 times this radius. Calculate the magnetic field strength at the proton due to the orbital motion of the electron in the n = 2 state.

The current in a wire along the x axis flows in the positive x direction. If a proton, located as shown in the figure, has an initial velocity in the positive z direction, it experiences