Download Magnetic Jeopardy

Magnetic Jeopardy
a.
b.
c.
d.
e.
1. Electrical charges and magnetic poles have many
similarities, but one difference is:
opposite magnetic poles repel.
one magnetic pole cannot create magnetic poles in other materials.
a magnetic pole cannot b e isolated.
magnetic poles do not produce magnetic fields.
magnetic poles produce only alt ernating fields.
2. Geophysicists today generally attribute the existence of the
Earth's magnetic field to which of the following?
a.
convection currents within the liquid interior
b.
iron ore deposits in the crust
c.
nickel-iron deposits in the crust
d.
solar flares
e.
iron-cobalt deposits in the crust
3. The magnetic pole of the Earth nearest the geographic
North Pole corresponds to which of the following?
a.
b.
c.
d.
a magnetic north pole
a magnetic south pole
a magnetic arctic pole
a magnetic antarctic pole
4. An electron which moves with a speed of 3.0  104 m/s
parallel to a uniform magnetic field of 0.40 T experiences
a force of what magnitude? (e = 1.6  1019 C)
5. 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?
a.
b.
c.
d.
e.
out of the page
to the right
to the left
into the page
from top edge to bottom edge of the page
6. 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?
a.
out of the page
b.
into the page
c.
from bottom edge to top edge of the page
d.
e.
from right to left across the page
from left to right across the page
7. There is a magnetic force on a particle. It is
possible that the particle is:
a.
b.
c.
d.
e.
uncharged.
stationary.
moving in the direction of the magnetic field.
not part of a wire.
moving opposite the direction of the magnetic
field.
8. A 2.0-m wire segment carrying a current of 0.60 A
oriented parallel to a uniform magnetic field of 0.50
T experiences a force of what magnitude?
a.
b.
c.
d.
e.
6.7 N
0.30 N
0.15 N
0.60 N
zero
9. A copper wire of length 25 cm is in a magnetic field of 0.20 T. If it
has a mass of 10 g, what is the minimum current through the wire
that would cause a magnetic force equal to its weight?
a.
b.
c.
d.
e.
1.3 A
1.5 A
2.0 A
4.9 A
5.2 A
10. A horizontal wire of length 3.0 m carries a current of 6.0 A and
is oriented so that the current direction is 50 S of W. The Earth's
magnetic field is due north at this point and has a strength of 0.14 
104 T. What is the direction of the force on the wire?
a.
b.
c.
d.
e.
out of the Earth's surface
toward the Earth's surface
due east
40 S of E
due west
11. A proton moving with a speed of 3.0  105 m/s perpendicular
to a uniform magnetic field of 0.20 T will follow which of the
paths described below? (mp = 1.67  1027 kg)
a.
b.
c.
d.
a straight line path
a circular path of 1.6 cm radius
a circular path of 3.1 cm radius
a circular path of 0.78 cm radius
e.
a circular path of 0.39 cm radius
12. The path of a charged particle moving parallel to a
uniform magnetic field will be a:
a.
b.
c.
d.
e.
straight line.
circle.
ellipse.
parabola.
hyperbola.
13. 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:
a.
b.
c.
d.
e.
Maxwell.
Ampere.
Oersted.
Tesla.
Faraday.
14. A current in a long, straight wire produces a magnetic
field. The magnetic field lines:
a.
b.
go out from the wire to infinity.
come in from infinity to the wire.
c.
form circles that pass through the wire.
d.
form circles that go around the wire.
e.
are parallel to the wire.
15. Electrical energy passes down the funnel of a large tornado every second.
Measurements taken in Oklahoma at a distance of 9.00 km from a large
tornado showed an almost constant magnetic field of 1.50  108 T associated
with the tornado. What was the average current going down the funnel?
a.
b.
c.
d.
e.
450 A
675 A
950 A
1 500 A
1 750 A
16. Two parallel conductors each of 0.50 m length, separated by 5.0  103
m and carrying 3.0 A in opposite directions, will experience what type and
magnitude of mutual force? (magnetic permeability in empty space
17. Superconductors can carry very large currents with no resistance.
If a superconducting wire is formed into a solenoid of length 50.0 cm
with 500 turns, what is the magnetic field inside the solenoid when
the current is 104 A? (µ0 = 4  107 Tm/A)
a.
1.25 T
b.
2.50 T
c.
6.28 T
d.
12.6 T
e.
25.2 T
18. According to Lenz's law the direction of an induced
current in a conductor will be that which tends to produce
which of the following effects?
a.
enhance the effect which produces it
b.
produce a greater heating effect
c.
produce the greatest voltage
d.
oppose the effect which produces it
e.
produce the greatest magnetic field
19. A square coil, enclosing an area with sides 2.0 cm long, is
wrapped with 2 500 turns of wire. A uniform magnetic field
perpendicular to its plane is turned on and increases to 0.25 T during
an interval of 1.0 s. What average voltage is induced in the coil?
a.
0.25 V
b.
0.12 V
c.
2.0 V
d.
2.5 V
e.
1.8 V
20. A flat coil of wire consisting of 20 turns, each with an area of 50 cm2,
is positioned perpendicularly to a uniform magnetic field that increases its
magnitude at a constant rate from 2.0 T to 6.0 T in 2.0 s. If the coil has a
total resistance of 0.40 , what is the magnitude of the induced current?
a. 70 mA
b.
140 mA
c.
500 mA
d.
800 mA
e.
900 mA
21. A coil is placed in a changing magnetic field and an emf
is induced. What happens to the induced emf if the rate of
change of magnetic field quadruples?
a.
b.
There is no change.
The emf doubles.
c.
d.
e.
The emf quadruples.
The emf increases by a factor of 16.
The emf halves.
22. The basic function of the electric generator is which of
the following conversion processes?
a.
b.
mechanical energy to electrical
electrical energy to mechanical
c.
d.
e.
low voltage to high or vice versa
alternating current to direct
direct current to alternating
23. A 500-turn circular coil with an area of 0.050 0 m2 is mounted on a
rotating frame, which turns at a rate of 20.0 rad/s in the presence of a
0.050 0-T uniform magnetic field that is perpendicular to the axis of
rotation. What is the max emf in the coil?
a.
b.
c.
d.
e.
zero
12.5 V
21.6 V
25.0 V
37.5 V
24. What is the minimum frequency with which a 200-turn, flat
coil of cross sectional area 300 cm2 can be rotated in a uniform
30-mT magnetic field if the maximum value of the induced emf
is to equal 8.0 V?
a.
0.030 Hz
b.
c.
d.
e.
2.9 Hz
7.1 Hz
8.4 Hz
4.3 Hz
25.