Chapter 19 PHYS 2020

A proton and a deuteron are moving with equal velocities perpendicular to a uniform magnetic field. A deuteron has the same charge as the proton but has twice its mass. The ratio of the acceleration of the proton to that of the deuteron is:

1

Different units can be used to measure the same physical quantity, differing only by some multiplicative factor. The cgs unit for magnetic field, the gauss, is equal to ___ Tesla.

10^-4

The term magnetic declination refers to which of the following?

Angle between directions to true north and magnetic north

Geophysicists today generally attribute the existence of the Earth's magnetic field to which of the following?

Convection currents within the liquid interior

The force exerted on a current-carrying wire located in an external magnetic field is directly proportional to which of the following?

Current strength and field strength

If a proton is released at the equator and falls toward the Earth under the influence of gravity, the magnetic force on the proton will be toward the:

East

The force on a charged particle created by its motion in a magnetic field is maximum at what angle between the particle velocity and field?

90 degrees

If a charged particle is moving in a uniform magnetic field, its path can be:

A straight line, circle or helix

Electron diffraction

Effects on electrons due to wave-like interference of electrons with matter

Electromagnetic radiation

Energy carried by electromagnetic waves throughout space

Magnetism had been a known phenomenon for some time before its relation to electric currents was found. That a current in a wire produces a magnetic field was discovered by:

Faraday

The current in a long wire creates a magnetic field in the region around the wire. How is the strength of the field at distance r from the wire center related to the magnitude of the field?

Field inversely proportional to r

A current in a long, straight wire produces a magnetic field. The magnetic field lines:

Form circles that go around the wire

The right hand rule allows one to find a property of the interaction of a magnetic field with a charged particle. The right-hand rule applied to moving charges:

Gives the direction of the force on a charge moving in a magnetic field

In a mass spectrometer, an ion will have a smaller radius for its circular path if:

If the charge is greater

EMF Self-Inductance

Induced EMF produced in coil by changing current

A current in a solenoid with N turns creates a magnetic field at the center of that loop. The field strength is directly proportional to:

The number of turns in the loop and current strength

Consider two long, straight parallel wires, each carrying a current l. If the currents are flowing in opposite directions:

The two wires will repel each other

Two insulated current-carrying straight wires of equal length are arranged in the lab so that Wire A carries a current northward and Wire B carries a current eastward, the wires crossing at their midpoints separated only by their insulation. Which of the following statements are true?

There are forces, but the net force on each wire is zero.

A stationary positive charge +Q is located in a magnetic field B, which is directed toward the right as indicated. The direction of the magnetic force on Q is:

There is no magnetic force.

Assume that a uniform magnetic field is directed into this page. If an electron is released with an initial velocity directed from the bottom edge to the top edge of the page, which of the following describes the direction of the resultant force acting on the electron?

To the right

Electroweak force

Unification of electromagnetic and weak forces

Farad

Unit of capacitance (one coulomb per volt)

Right-hand rules

Used to find force on current or moving particle in magnetic field; used to find direction of magnetic field caused by current or of induced

Electromagnetic waves

Wave consisting of oscillating electric and magnetic field that move at speed of light through space

Which of the following devices makes use of an electromagnet?

Both a loudspeaker and a galvanometer

The magnetic field of the Earth is believed responsible for which of the following?

Deflection of charged cosmic rays

Electromagnet

Device that uses an electric current to produce a concentrated magnetic field

Transformer

Device to transform energy from one electrical circuit to another by means of mutual inductance between two coils

A circular current loop is placed in an external magnetic field. How is the torque related to the radius of the loop?

Directly proportional to radius squared

A wire is lying horizontally in the north-south direction and the horizontal magnetic field is toward the east. Some positive charges in the wire move north and an equal number of negative charges move south. The direction of the force on the wire will be:

Down, into the page

A proton is released such that its initial velocity is from right to left across this page. The proton's path, however, is deflected in a direction toward the bottom edge of the page due to the presence of a uniform magnetic field. What is the direction of this field?

Into the page

Which of the following is not a hard magnetic material?

Iron

When an electromagnet has an iron core inserted, what happens to the strength of the magnet?

It increases

A soft magnetic material has which property?

It is easy to magnetize

Electrical charges and magnetic poles have many similarities, but one difference is:

Magnetic poles cannot be isolated

Ferromagnetic materials

Materials in which large internal magnetic fields are generated by cooperative action of electrons

When a magnetic field causes a charged particle to move in a circular path, the only quantity listed below which the magnetic force changes significantly as the particle goes around in a circle is the particle's:

Momentum

There is a magnetic force on a particle. It is possible that the particle is:

Not part of a wire

Electromagnetic force

One of fundamental forces due to electrical charges, both static and moving

A proton moves across the Earth's equator in a northeasterly direction. At this point the Earth's magnetic field has a direction due north and is parallel to the surface. What is the direction of the force acting on the proton at this instant?

Out of the Earth's surface

The direction of the force on a current carrying wire located in an external magnetic field is which of the following?

Perpendicular to the current and perpendicular to the field

Electromotive force

Potential difference produced by electromagnetic induction

Electromagnetic induction

Production of electric field or current due to change in magnetic flux

The magnetic domains in a non-magnetized piece of iron are characterized by which orientation?

Random

Electron cloud

Region of high probability of finding an electron around an atom

Transistor

Semiconductor device that controls large current by means of small voltage changes

Magnetic field

Space around a magnet throughout which a magnetic force exists

The path of a charged particle moving parallel to a uniform magnetic field will be a:

Straight line

Electron

Subatomic particle of small mass and negative charge found in every atom

Which of the following locations has the smallest (in magnitude) magnetic declination?

The South Carolina - Georgia border

The current in a solenoid coil creates a magnetic field inside that coil. The field strength is directly proportional to:

The current

The magnetic pole of the Earth nearest the geographic North Pole corresponds to which of the following?

The magnetic South Pole