PHY 204 Quiz 5

Complete the following statement: According to today’s scientists, magnetic monopoles

• have no mass.

• have no charge.

• are found in abundance in the most distant parts of the universe

• do not exist anywhere in the universe

• are the antiparticles for magnetic dipoles.

What would you get if you took a bar magnet and cut it in half?

• two pieces, one a north pole and one a south pole

• two shorter magnets, each with a north pole and a south pole

• two pieces, both non-magnetic

• a molten mess from the energy released from within the magnet upon cutting

• an electric shock

Which of the following choices concerning the net magnetic flux through any enclosed surface is true according to Gauss’ law for magnetic fields?

• The net magnetic flux in this case would be a vector quantity equal to the enclosed magnetic field.

• The net magnetic flux in this case would be a vector quantity equal to the number of magnetic monopoles passing through the surface per unit time.

• The net magnetic flux in this case would be a positive scalar quantity.

• The net magnetic flux in this case would be equal to zero.

• The net magnetic flux in this case would be a negative scalar quantity

What is produced from a changing electric field?

• an electric field directed perpendicularly to the changing field

• a magnetic flux

• a magnetic field directed perpendicularly to the changing field

• lightning

• an electric field directed parallel to the changing field

. A parallel plate capacitor is being charged by a constant current i. During the charging, the electric field within the plates is increasing with time. Which one of the following statements concerning the magnetic field between the plates is true?

• The magnetic field within a parallel plate capacitor is always equal to zero tesla.

• The induced magnetic field is directed antiparallel to the increasing electric field.

• The induced magnetic field strength has its largest value at the center of the plates and decreases linearly toward the edges of the plates.

• The induced magnetic field strength has the same magnitude within the plates of the capacitor, except near the edges, at a given time

• The induced magnetic field strength is zero tesla near the center of the plates and increases as r increases toward the edges of the plates

What is a displacement current?

• a fictitious current across the plates of a capacitor

• charged particles moving in a changing magnetic field

• charged particle moving in a changing electric field

• the movement of the positive nuclei within atoms in response to a changing electric field

• the movement of the positive nuclei within atoms in response to a changing magnetic field

By making use of the concept of displacement current, we can find the induced magnetic field strength within a charging capacitor. Consider a parallel plate capacitor with circular plates of radius R. Which of the following expressions gives the correct relationship between the induced magnetic field strength B at radius r from the center?

• B∝r

• B∝1/R

• B=constant

• B∝R²

• B∝1/r²

Which one of the following is not one of Maxwell’s fundamental equations of electromagnetism?

• Gauss’ law for electricity

• Coulomb’s law

• Faraday’s law

• Ampere-Maxwell law

• Gauss’ law for magnetism

Which one of the following choices is the generally accepted reason for the changing of the Earth’s magnetic field over time?

• The field has changed because the Hubble constant has changed.

• The field has changed as the Earth has gone through numerous global warming and cooling cycles

• The field has changed as the Earth’s rotation has slowed down over time.

• The field has changed as a result of numerous asteroid collisions with the Earth over time

• The reason for the changing field has yet to be determined.

The direction of the magnetic field at any location of the Earth’s surface is commonly specified in terms of two field angles. What are the names given to these two angles?

• latitude and longitude

• oblique and obtuse

• dihedral and euclidean

• squine and novile

• declination and inclination