5) Physics Final

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

90 degrees

The magnetic field of the earth nearest the geographic north pole corresponds to which of the following?

A magnetic south pole

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

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

There must always be at least two, a north pole and a south

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, what direction does the resultant force acting on the electron travel

To the right (right hand rule)

The magnetic field of the Earth is believed responsible for which of the following? a) deflection of both charged and uncharged cosmic rays b) deflection of charged cosmic rays c) ozone in the upper atmosphere d) solar flares

Deflection of charged cosmic rays

A wire is lying 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)

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

It increases.

Which statement regarding the force of a magnetic field on a current-carrying wire is true? a) The magnetic force on the wire is independent of the direction of the current b) The force on the wire is directed parallel to both the wire and the magnetic field c) The force takes its largest value when the magnetic field is parallel to the wire d) None of the above

None of the above are true

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

Two parallel wires carry a current I in the same direction. Midway between these wires is a third wire, also parallel to the other two, which carries a current 0.4 I, but in the direction opposite from the first two wires. In which direction are the net forces on the outer wires?

Since the net forces are zero, there is no direction.

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

Straight line

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

The current