CH. 19 Magnetism

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

45

The term magnetic declination refers to which of the following?

Angle between directions to true north and magnetic north

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

Any of the above

The units for magnetic field are

B, teslas

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

Convection currents within the liquid interior

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

Current

Electrical charges and magnetic poles have many similarities but one differnce is

A magnetic pole cannot be isolated

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

Field inversely proportional to r

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

Filed strength or Current strength

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

Form circles that go around the wire

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

The two wires will repel each other

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

There are forces, but the net force on each wire is zero. [arrows represent force created from the field

A solenoid can also be called an electromagnet.

True

A solenoid will act like a bar magnet having a north and south pole.

True

Magnetic field lines in a bar magnet are directed out of the north pole and into the south pole of the magnet.

True

The needle of a compass will point in a direction parallel to the magnetic field lines.

True

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

Deflection of charged cosmic rays

A proton is releassed 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 magnatic field. What is the firection of this field?

Into the page

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

Its charge is greater

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

Momentum

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

Number of turns in the loop, or current strenght

A proton moves across the Earth's equator direction. At this point the Earth's magnetic field has a direction due north and i 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 extenal magnetic field is which of the following?

Perpendicular to the current or Perpendicular to the field

When a moving charge particle is placed in a magnetic field so that the velocity is perpendicular to the field the resulting motion will be a helical path.

Perpendicular to the velocity of a charged particle, the particle will undergo circular motion.

When trying to find the direction of the force produced by a magnetic field on a moving electron you use the left hand rule.

Right hand rule

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

Straight line

The split ring contacts in a motor are called the armature for a

commutator