29. Sources of Magnetic Field

A compass needle’s magnetic north pole points toward which of the following?

What important role does the $\mathrm{magnetic} \mathrm{field}$ play for our planet?

A rectangular wire loop moves with constant velocity into a region where the right edge of the circuit enters a uniform magnetic field of magnitude $50mT$. If the magnetic field is directed into the page and the velocity of the loop is perpendicular to the field, what is the direction of the induced current in the loop as it enters the field?

How are magnetic field line models helpful in understanding the magnetic field produced by moving charges?

A thin ring of radius $R$ carries a total charge $Q$ and rotates with angular speed $\omega$ about its axis. What is the ring's magnetic dipole moment?

Which of the following correctly identifies the two poles of a magnet?

Which of the following electromagnets would produce the greatest magnetic field at the center of the coil ($B$)?

When a compass is used on $\mathrm{Earth}$, in which direction does the north magnetic side of the compass needle point?

Two long, straight, parallel wires carry currents in the same direction. What is the direction of the magnetic field produced by wire $1$ at the location of wire $2$?

Which of the following best explains what makes a magnet different from a piece of iron that is not magnetic?

Which of the following elements does not produce a magnetic field under normal conditions?

Which of the following statements about Earth's magnetic field is most accurate?

A magnetically soft material is placed in a strong $B$ field. What is the most likely outcome?

A bar magnet is moved toward a conducting coil as shown. What happens to the magnetic field $B$ of the magnet through the coil as the magnet approaches?

If four small bar magnets are attached together end-to-end to form a single straight line, how many distinct $B$ fields will be produced by the combined system?