Name
Chapter 9 Review WS
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) A book weighs 6 N. When held at rest above your head the net force on the book is
A) 9.8 N.
B) -6 N.
C) 6 N.
D) 0 N.
1)
2) What condition or conditions are necessary for rotational equilibrium?
A) Fx = 0
B)
=0
=0
C) Fx = 0,
D) Fx = 0, Fy = 0
2)
3) A rocket moves through outer space with a constant velocity of 9.8 m/s. What net force acts on it?
A) a force equal to its weight on Earth, mg
B) a force equal to the gravity acting on it
C) The net force is zero.
D) cannot be determined without more information
3)
4) Stress is
A) the strain per unit length.
C) applied force per cross-sectional area.
4)
B) the same as force.
D) the ratio of the change in length.
5) Strain is
A) the ratio of the change in length to the original length.
B) the ratio of stress to elastic modulus.
C) the stress per unit area.
D) the applied force per unit area.
5)
6) A lever is 5.0 m long. The distance from the fulcrum to the weight to be lifted is 1.0 m. If a worker
pushes on the opposite end with 400 N, what is the maximum weight that can be lifted?
A) 2000 N
B) 1600 N
C) 80 N
D) 100 N
6)
7) A boy and a girl are balanced on a massless seesaw. The boy has a mass of 75 kg and the girl's
mass is 50 kg. If the boy sits 2.0 m from the pivot point on one side of the seesaw, where must the
girl sit on the other side?
A) 2.5 m
B) 1.3 m
C) 2.3 m
D) 3.0 m
7)
8) A heavy boy and a light girl are balanced on a massless seesaw. If they both move forward so that
they are one-half their original distance from the pivot point, what will happen to the seesaw?
A) Nothing, the seesaw will still be balanced.
B) The side the girl is sitting on will tilt downward.
C) The side the boy is sitting on will tilt downward.
D) It is impossible to say without knowing the masses and the distances.
8)
9) A mass is hung from identical wires made of aluminum, brass, copper, and steel. Which wire will
stretch the least?
A) brass
B) aluminum
C) copper
D) steel
E) all the same
9)
1
10) A 10-m uniform beam of weight 100 N is supported by two ropes at the ends. If a 400-N person
sits at 2.0 m from the left end of the beam, what is the tension in the left rope?
A) 370 N
B) 500 N
C) 130 N
D) 250 N
10)
11) A 500-N person stands on a uniform board of weight 100 N and length 8.0 m. The board is
supported at each end. If the support force at the right end is three times that at the left end, how
far from the right end is the person?
A) 6.4 m
B) 1.6 m
C) 4.0 m
D) 2.0 m
11)
12) A 5000-N force compresses a steel block by 0.0025 cm. How much force would be needed to
compress the block by 0.0125 cm?
A) 2500 N
B) 5000 N
C) 1000 N
D) 25000 N
12)
13) A mass of 50 kg is suspended from a steel wire of diameter 1.0 mm and length 11.2 m. How much
will the wire stretch? The Young's modulus for steel is 20 × 1010 N/m2 .
A) 3.5 cm
B) 1.5 cm
C) 4.5 cm
D) 2.5 cm
13)
14) A massless scaffold is held up by a wire at each end. The scaffold is 12 m long. A 300-N box sits 4.0
m from the left end. What is the tension in each wire?
A) left wire = 200 N; right wire = 100 N
B) left wire = 900 N; right wire = 2700 N
C) left wire = 100 N; right wire = 200 N
D) left wire = 2700 N; right wire = 900 N
14)
15) A shear force of 400 N is applied to one face of an aluminum cube with sides of 30 cm. What is the
resulting relative displacement? (The shear modulus for aluminum is 2.5 × 1010 N/m2 )
A) 4.4 × 10-8 m
B) 5.3 × 10-8 m
C) 1.9 × 10-8 m
D) 8.2 × 10-8 m
15)
FIGURE 9-1
16) Assuming the lower arm has a mass of 2.8 kg and its CG is 12 cm from the elbow-joint pivot, how
much force must the extensor muscle in the upper arm exert on the lower arm to hold a 7.5 kg shot
put (Fig. 9-1)?
A) 1500 N
B) 1000 N
C) 100 N
D) 500 N
2
16)
NAME
Chapter 23 Review Sheet
MULTIPLE CHOICE. Choose the one alternative that best
completes the statement or answers the question.
8) When a person stands 40 cm in front of a
cosmetic mirror (concave mirror), the erect
image is twice the size of the object. What is
the focal length of the mirror?
A) 27 cm
B) 160 cm
C) 80 cm
D) 40 cm
1) A laser beam strikes a plane's reflecting surface
with an angle of incidence of 52°. What is the
angle between the incident ray and the
reflected ray?
A) 52°
B) 90°
C) 105°
D) 45°
9) An object is 14 cm in front of a convex mirror.
The image is 5.8 cm behind the mirror. What
is the focal length of the mirror?
A) -8.2 cm
B) -4.1 cm
C) -9.9 cm
D) -20 cm
2) How far are you from your image when you
stand 0.75 m in front of a vertical plane mirror?
A) 0.75 m
B) 3.0 m
C) 1.5 m
D) none of the given answers
10) A convex spherical mirror has a focal length of
-20 cm. An object is placed 30 cm in front of
the mirror on the mirror's axis. Where is the
image located?
A) 60 cm behind the mirror
B) 12 cm in front of the mirror
C) 60 cm in front of the mirror
D) none of the given answers
3) A spherical concave mirror has a radius of
curvature of 20 cm. How far from the mirror is
the focal point located?
A) 20 cm
B) 30 cm
C) 10 cm
D) 40 cm
11) An object is 8.90 cm tall. The image is 7.80 cm
tall, and 14.8 cm from a convex mirror. What
is the mirror's focal length?
A) -120 cm
B) -16.9 cm
C) -105 cm
D) -13.0 cm
4) A object is 12 cm in front of a concave mirror,
and the image is 3.0 cm in front of the mirror.
What is the focal length of the mirror?
A) 2.4 cm
B) 4.0 cm
C) 15 cm
D) 1.3 cm
12) If a material has an index of refraction of 1.50,
what is the speed of light through it?
A) 6.00 × 108 m/s
B) 2.00 × 108 m/s
8
C) 3.00 × 10 m/s
D) 4.50 × 108 m/s
5) A concave spherical mirror has a focal length
of 20 cm. An object is placed 10 cm in front of
the mirror on the mirror's axis. Where is the
image located?
A) 20 cm in front of the mirror
B) 6.7 cm in front of the mirror
C) 20 cm behind the mirror
D) 6.7 cm behind the mirror
13) A light ray in air is incident on an air to glass
interface at an angle of 45° and is refracted at
an angle of 30° to the normal. What is the
index of refraction of the glass?
A) 1.31
B) 1.41
C) 1.74
D) 1.23
6) An object is 5.7 cm from a concave mirror. The
image is 4.7 cm tall, and 10 cm from the mirror.
How tall is the object?
A) 12 cm
B) 8.2 cm
C) 11 cm
D) 2.7 cm
14) Light passes from air to water. The incoming
ray is at an angle of 17.0° to the normal. The
index of refraction is 1.33. What is the angle in
the water?
A) 22.9°
B) 12.7°
C) 22.6°
D) 18.3°
7) An object is placed 15 cm from a concave
mirror of focal length 20 cm. The object is 4.0
cm tall. How tall is the image?
A) 1.0 cm
B) 2.0 cm
C) 16 cm
D) 8.0 cm
1
15) A diver is 1.2 m beneath the surface of a still
pond of water. At what angle must the diver
shine a beam of light toward the surface in
order for a person on a distant bank to see it?
(The index of refraction for water is 1.33.)
A) 41°
B) 59°
C) 49°
D) 90°
22) When an object is 40 m in front of a converging
lens the inverted image is half the size of the
object. What is the focal length of this lens?
A) 40 cm
B) 13 cm
C) 20 cm
D) 53 cm
23) How far from a 50-mm focal length lens, such
as is used in many 35-mm cameras, must an
object be positioned if it is to form a real image
magnified in size by a factor of three?
A) 52 mm
B) 58 mm
C) 46 mm
D) 67 mm
16) A beam of light traveling in air is incident on a
slab of transparent material. The incident
beam and the refracted beam make angles of
40° and 26° to the normal. What is the speed of
light in the transparent material?
A) 1.0 × 108 m/s
B) 2.0 × 108 m/s
C) 3.0 × 108 m/s
D) 2.3 × 108 m/s
24) A double convex (convex-convex) thin lens
has radii of curvature 46 cm, and is made of
glass of index of refraction n = 1.60. What is
the focal length?
A) 18 cm
B) 38 cm
C) 30 cm
D) infinite
17) A substance has an index of refraction of 1.46.
Light is passing through it at 53.0°. At what
angle will it leave into the air?
A) 43.2°
B) 33.2°
C) It will not leave.
D) 59.1°
25) An object is 6.0 cm tall, and is in front of a
diverging lens. The image is 2.5 cm tall, and
7.5 cm from the lens. What is the focal length
of the lens?
A) -13 cm
B) -18 cm
C) -6.0 cm
D) -7.5 cm
18) What is the critical angle for light traveling
from crown glass (n = 1.52) into water (n =
1.33)?
A) 48°
B) 42°
C) 57°
D) 61°
19) The critical angle for a substance is measured
at 53.7°. Light enters from air at 45.0°. At what
angle will it continue?
A) 53.7°
B) 45.0°
C) 34.7°
D) It will not continue, but be totally
reflected.
20) An object is 12 cm in front of a converging lens
with focal length 4 cm. Where is the image?
A) 6.0 cm behind the lens
B) 6.0 cm in front of the lens
C) 8.0 cm behind the lens
D) 4.0 cm in front of the lens
21) A 14-mm tall object is 4.0 mm from a
converging lens. If the image is 4.0 mm tall,
how far is it from the lens?
A) 1.1 mm
B) 1.4 mm
C) 8.7 mm
D) 14 mm
2
NAME
Ch 24 Review
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) When a light wave enters into a medium of different optical density,
A) its speed and wavelength change.
B) its frequency and wavelength change.
C) its speed and frequency change.
D) its speed, frequency, and wavelength change.
1)
2) A beam of light (f = 5.0 × 1014 Hz) enters a piece of glass (n = 1.5). What is the frequency of the
light while it is in the glass?
A) 7.5 × 1014 Hz
B) 3.3 × 1014 Hz
14
C) 5.0 × 10 Hz
D) none of the given answers
2)
3) Light has a wavelength of 600 nm in a vacuum. It passes into glass, which has an index of
refraction of 1.50. What is the wavelength of the light in the glass?
A) 600 nm
B) 300 nm
C) 400 nm
D) 500 nm
3)
4) Light of wavelength 550 nm in vacuum is found to travel at 1.96×108 m/s in a certain liquid.
Determine the index of refraction of the liquid.
A) 5.50
B) 1.96
C) 1.53
D) 0.65
4)
5) At the first maxima on either side of the central bright spot in a double-slit experiment, light from
each opening arrives
A) in phase.
B) 180° out of phase.
C) 90° out of phase.
D) none of the given answers
5)
6) At the first minima on either side of the central bright spot in a double-slit experiment, light from
each opening arrives
A) 180° out of phase.
B) in phase.
C) 90° out of phase.
D) none of the given answers
6)
7) Two thin slits are 6.00 µm apart. Monochromatic light falls on these slits, and produces a fifth
order interference fringe at an angle of 32.3°. What is the wavelength of the light?
A) 641 nm
B) 614 nm
C) 164 nm
D) 416 nm
7)
8) Light of wavelength 575 nm falls on a double-slit and the third order bright fringe is seen at an
angle of 6.5°. What is the separation between the double slits?
A) 5.0 µm
B) 15 µm
C) 20 µm
D) 10 µm
8)
9) In a Young's double slit experiment, if the separation between the two slits is 0.050 mm and the
distance from the slits to a screen is 2.5 m, find the spacing between the first-order and
second-order bright fringes for light with wavelength of 600 nm.
A) 6.0 cm
B) 4.5 cm
C) 3.0 cm
D) 1.5 cm
9)
10) Two thin slits are 0.050 mm apart. Monochromatic light of wavelength 634 nm falls on the slits. If
there is a screen 6.0 m away, how far apart are adjacent interference fringes?
A) 7.6 mm
B) 7.6 cm
C) 0.76 mm
D) 76 cm
1
10)
11) A parallel light beam containing two wavelengths, 480 nm and 700 nm, strikes a plain piece of
glass at an angle of incidence of 60°. The index of refraction of the glass is 1.4830 at 480 nm and
1.4760 at 700 nm. Determine the angle between the two beams in the glass.
A) 0.15°
B) 0.25°
C) 0.20°
D) 0.10°
11)
12) A single slit, which is 0.050 mm wide, is illuminated by light of 550 nm wavelength. What is the
angular separation between the first two minima on either side of the central maximum?
A) 0.54°
B) 0.36°
C) 0.63°
D) 0.47°
12)
13) Light of wavelength 687 nm is incident on a single slit 0.75 mm wide. At what distance from the
slit should a screen be placed if the second dark fringe in the diffraction pattern is to be 1.7 mm
from the center of the screen?
A) 0.39 m
B) 1.9 m
C) 1.1 m
D) 0.93 m
13)
14) Light of wavelength 610 nm is incident on a slit 0.20 mm wide and the diffraction pattern is
produced on a screen that is 1.5 m from the slit. What is the width of the central maximum?
A) 0.92 cm
B) 0.68 cm
C) 1.2 cm
D) 0.34 cm
14)
15) Light of wavelength 580 nm is incident on a slit of width 0.300 mm. An observing screen is placed
2.00 m from the slit. Find the position of the first order dark fringe from the center of the screen.
A) 7.7 mm
B) 1.9 mm
C) 0.26 mm
D) 3.9 mm
15)
16) A diffraction grating has 5000 lines per cm. The angle between the central maximum and the
fourth order maximum is 47.2°. What is the wavelength of the light?
A) 367 nm
B) 183 nm
C) 138 nm
D) 637 nm
16)
17) Monochromatic light is incident on a grating that is 75 mm wide and ruled with 50,000 lines. The
second-order maximum is seen at 32.5°. What is the wavelength of the incident light?
A) 202 nm
B) 403 nm
C) 806 nm
D) 605 nm
17)
18) White light is spread out into spectral hues by a grating. If the grating has 2000 lines per
centimeter, at what angle will red light (640 nm) appear in the first order?
A) 11.2°
B) 7.35°
C) 3.57°
D) 13.4°
18)
19) A soap bubble has an index of refraction of 1.33. What minimum thickness of this bubble will
ensure maximum reflectance of normally incident 530 nm wavelength light?
A) 398 nm
B) 199 nm
C) 24.9 nm
D) 99.6 nm
19)
20) A glass plate 2.5 cm long is separated from another glass plate at one end by a strand of someone's
hair (diameter 0.010 mm). How far apart are the adjacent interference bands when viewed with
light of wavelength 600 nm?
A) 0.75 mm
B) 1.0 mm
C) 0.50 mm
D) 0.25 mm
20)
21) How far above the horizon is the Moon when its image reflected in calm water is completely
polarized?
A) 46.8°
B) 53.1°
C) 43.2°
D) 36.9°
21)
22) What is the Brewster's angle for light traveling in vacuum and reflecting off a piece of glass of index
of refraction 1.48?
A) 39.8°
B) 31.9°
C) 45.3°
D) 56.0°
22)
2
NAME
CH 16 Review
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) An atom has more electrons than protons. The atom is
A) impossible.
B) a negative ion.
C) a positive ion.
D) a superconductor.
2) How can a negatively charged rod charge an electroscope positively?
A) by induction
B) by deduction
C) by conduction
1)
D) It cannot.
2)
3) A negatively charged rod is brought near one end of an uncharged metal bar. The end of the metal
bar farthest from the charged rod will be charged
A) positive.
B) neutral.
C) negative.
D) none of the given answers
3)
4) Two charges are separated by a distance d and exert mutual attractive forces of F on each other. If
the charges are separated by a distance of d/3, what are the new mutual forces?
A) F/9
B) F/3
C) 9F
D) 3F
4)
5) An electron and a proton are separated by a distance of 1.0 m. What happens to the magnitude of
the force on the proton if a second electron is placed next to the first electron?
A) It goes to zero.
B) It will not change.
C) It doubles.
D) It quadruples.
5)
6) The charge carried by one electron is e = -1.6 × 10-19 C. The number of electrons necessary to
produce a charge of -1.0 C is
A) 6.25 × 109 .
B) 1.6 × 1019.
18
C) 6.25 × 10 .
D) none of the given answers
6)
7) Two point charges, separated by 1.5 cm, have charge values of 2.0 and -4.0 µC, respectively. What
is the magnitude of the electric force between them?
A) 160 N
B) 360 N
C) 320 N
D) 400 N
7)
8) Three point charges are placed on the x-axis. A charge of +2.0 µC is placed at the origin, -2.0 µC to
the right at x = 50 cm, and +4.0 µC at the 100 cm mark. What are the magnitude and direction of
the electrostatic force which acts on the charge at the origin?
A) 0.14 N right
B) 0.072 N left
C) 0.072 N right
D) 0.14 N left
8)
9) Q1 = 6.0 nC is at (0.30 m, 0); Q2 = -1.0 nC is at (0, 0.10 m); Q3 = 5.0 nC is at (0, 0). What is the
magnitude of the net force on the 5.0 nC charge?
A) 7.2 × 10-6 N
B) 5.4 × 10-6 N
C) 3.0 × 10-6 N
D) 4.5 × 10-6 N
9)
10) Three identical charges of 3.0 µC are placed at the vertices of an equilateral triangle which
measures 30 cm on a side. What is the magnitude of the electrostatic force which acts on any one of
the charges?
A) 2.0 N
B) 1.6 N
C) 2.2 N
D) 1.8 N
1
10)
11) Consider point charges of +Q and +4Q, which are separated by 3.0 m. At what point, on a line
between the two charges, would it be possible to place a charge of -Q such that the electrostatic
force acting on it would be zero?
A) 1.0 m from the +Q charge
B) 1.0 m from the +4Q charge
C) There is no such point possible.
D) 0.60 m from the +Q charge
11)
12) Charge +2q is placed at the origin and charge -q is placed at x = 2a. Where can a third positive
charge +q be placed so that the force on it is zero?
A) 3.4a
B) 9.3a
C) 8.6a
D) 6.8a
12)
13) An electron is held up against the force of gravity by the attraction of a fixed proton some distance
above it. How far above the electron is the proton?
A) 1.5 m
B) 5.1 m
C) 3.7 m
D) 2.3 m
13)
14) A 5.0-C charge is 10 m from a small test charge. What is the magnitude of the electric field at the
location of the test charge?
A) 4.5 × 107 N/C
B) 4.5 × 109 N/C
C) 4.5 × 106 N/C
D) 4.5 × 108 N/C
14)
15) A 5.0-C charge is 10 m from a small test charge. What is the direction of the electric field?
A) perpendicular to a line joining the charges
B) away from the 5.0 C
C) toward the 5.0 C
D) none of the given answers
15)
16) Two point charges each have a value of 3.0 C and are separated by a distance of 4.0 m. What is the
electric field at a point midway between the two charges?
A) 18 × 107 N/C
B) 9.0 × 107 N/C
C) zero
D) 4.5 × 107 N/C
16)
17) A metal sphere of radius 10 cm carries a charge of +2.0 µC. What is the magnitude of the electric
field 5.0 cm from the sphere's surface?
A) 8.0 × 107 N/C
B) 4.0 × 105 N/C
C) 4.0 × 107 N/C
D) 8.0 × 105 N/C
17)
18) A force of 10 N acts on a charge of 5.0 µC when it is placed in a uniform electric field. What is the
magnitude of this electric field?
A) 0.50 MN/C
B) 2.0 MN/C
C) 1000 MN/C
D) 50 MN/C
18)
19) A Styrofoam ball of mass 0.120 g is placed in an electric field of 6000 N/C pointing downward.
What charge must be placed on the ball for it to be suspended?
A) -16.0 nC
B) -57.2 nC
C) -196 nC
D) -125 nC
19)
20) Two point charges of +3.0 µC and -7.0 µC are placed at x = 0 and x = 0.20 m. What is the
magnitude of the electric field at the point midway between them?
A) 3.6 × 106 N/C
B) 1.8 × 106 N/C
C) 9.0 × 106 N/C
D) 4.5 × 106 N/C
20)
21) Consider a square which is 1.0 m on a side. Charges are placed at the corners of the square as
follows: +4.0 µC at (0, 0); +4.0 µC at (1, 1); +3.0 µC at (1, 0); -3.0 µC at (0, 1). What is the
magnitude of the electric field at the square's center?
A) 1.3 × 105 N/C
B) 1.1 × 105 N/C
C) 1.5 × 105 N/C
D) 1.7 × 105 N/C
21)
2
NAME
Ch 17 Review
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) One joule per coulomb is a
A) newton.
B) electron-volt.
C) volt.
D) farad.
1)
2) Two identical aluminum objects are insulated from their surroundings. Object A has a net charge
of excess electrons. Object B is grounded. Which object is at a higher potential?
A) A
B) B
C) Both are at the same potential.
D) cannot be determined without more information
2)
3) For an electron moving in a direction opposite to the electric field
A) its potential energy decreases and its electric potential decreases.
B) its potential energy increases and its electric potential decreases.
C) its potential energy increases and its electric potential increases.
D) its potential energy decreases and its electric potential increases.
3)
4) Several electrons are placed on a hollow conducting sphere. They
A) become uniformly distributed on the sphere's outer surface.
B) clump together on the sphere's inner surface.
C) become uniformly distributed on the sphere's inner surface.
D) clump together on the sphere's outer surface.
4)
5) A negative charge is moved from point A to point B along an equipotential surface.
A) Work is both required and performed in moving the negative charge from point A to point B.
B) No work is required to move the negative charge from point A to point B.
C) Work is required to move the negative charge from point A to point B.
D) The negative charge performs work in moving from point A to point B.
5)
6) It takes 50 J of energy to move 10 C of charge from point A to point B. What is the potential
difference between points A and B?
A) 5.0 V
B) 0.50 V
C) 500 V
D) 50 V
6)
7) The net work done in moving an electron from point A, where the potential is -50 V, to point B,
where the potential is +50 V, is
A) zero.
B) +1.6 × 10-17 J.
C) -1.6 × 10-17 J.
D) none of the given answers
7)
8) A proton, initially at rest, is accelerated through an electric potential difference of 500 V. What is
the speed of the proton?
A) 2.2 × 105 m/s
B) 9.6 × 1010 m/s
C) 3.1 × 105 m/s
D) zero
8)
9) How much work does 9.0 V do in moving 8.5 × 1018 electrons?
A) 1.1 J
B) 12 J
C) 1.4 J
9)
1
D) 7.7 J
10) A 4.0-g object carries a charge of 20 µC. The object is accelerated from rest through a potential
difference, and afterward the ball is moving at 2.0 m/s. What is the magnitude of the potential
difference?
A) 800 V
B) 800 kV
C) 400 V
D) 400 kV
10)
11) A 6.0-V battery maintains the electrical potential difference between two parallel metal plates
separated by 1.0 mm. What is the electric field between the plates?
A) 600 V/m
B) zero
C) 6000 V/m
D) 6.0 V/m
11)
12) A uniform electric field, with a magnitude of 500 V/m, is directed parallel to the +x axis. If the
potential at x = 5.0 m is 2500 V, what is the potential at x = 2.0 m?
A) 500 V
B) 1000 V
C) 4000 V
D) 2000 V
12)
13) Consider a uniform electric field of 50 N/C directed toward the east. If the voltage measured
relative to ground at a given point is 80 V, what is the voltage at a point 1.0 m directly west of that
point?
A) 50 V
B) 130 V
C) 30 V
D) 80 V
13)
14) Two parallel plates, separated by 0.20 m, are connected to a 12-V battery. An electron released
from rest at a location 0.10 m from the negative plate. When the electron arrives at a distance 0.050
m from the positive plate, what is the potential difference between the initial and final points?
A) 2.4 V
B) 6.0 V
C) 4.8 V
D) 3.0 V
14)
15) Consider a uniform electric field of 50 N/C directed toward the east. If the voltage measured
relative to ground at a given point in the field is 80 V, what is the voltage at a point 1.0 m directly
south of that point?
A) zero
B) 80 V
C) 50 V
D) 30 V
15)
16) What is the potential at a distance of 5.0 × 10-10 m from a nucleus of charge +50e?
A) 170 V
B) 120 V
C) 140 V
D) 210 V
16)
17) Two 3.00-µC charges are at the ends of a meter stick. Find the electrical potential for the center of
the meter stick.
A) 2.70 × 104 V
B) zero
C) 5.40 × 104 V
D) 1.08 × 105 V
17)
18) A 5.0-nC charge is at (0, 0) and a -2.0-nC charge is at (3.0 m, 0). If the potential is taken to be zero
at infinity, what is the electric potential at point (0, 4.0 m)?
A) 11 V
B) 3.6 V
C) 7.7 V
D) 15 V
18)
19) A 5.0-nC charge is at (0, 0) and a -2.0-nC charge is at (3.0 m, 0). If the potential is taken to be zero
at infinity, what is the work required to bring a 1.0-nC charge from infinity to point (0, 4.0 m)?
A) 1.1 × 10-8 J
B) 3.6 × 10-9 J
C) 1.5 × 10-8 J
D) 7.7 × 10-9 J
19)
20) Four charges of equal charge +q are placed at the corners of a rectangle of sides a and b. What is the
potential at the center of the rectangle if q = 2.0 µC, a = 3.0 cm, and b = 4.0 cm?
A) 3.5 × 106 V
B) 2.9 × 106 V
C) 7.8 × 106 V
D) 1.3 × 106 V
20)
21) What charge appears on the plates of a 2.0-µF capacitor when it is charged to 100 V?
A) 150 µC
B) 50 µC
C) 100 µC
D) 200 µC
21)
2
22) A charge of 60 µC is placed on a 15 µF capacitor. How much energy is stored in the capacitor?
A) 120 µJ
B) 4.0 J
C) 240 µJ
D) 120 J
22)
23) A parallel-plate capacitor consists of plates of area 1.5 × 10-4 m2 and separated by 1.0 mm. The
capacitor is connected to a 12-V battery. What is the capacitance?
A) 1.3 × 10-15 F
B) 2.6 × 10-12 F
C) 1.3 × 10-12 F
D) 2.6 × 10-15 F
23)
24) A parallel-plate capacitor consists of plates of area 1.5 × 10-4 m2 and separated by 1.0 mm. The
capacitor is connected to a 12-V battery. What is the electric field between the plates?
A) 1.2 × 104 V/m
B) 1.2 × 103 V/m
C) 1.2 × 102 V/m
D) 12 V/m
24)
25) A 15-µF capacitor is connected to a 50-V battery and becomes fully charged. The battery is
removed and a slab of dielectric that completely fills the space between the plates is inserted. If the
dielectric has a dielectric constant of 5.0, what is the capacitance of the capacitor after the slab is
inserted?
A) 1.0 µF
B) 75 µF
C) 3.0 µF
D) 20 µF
25)
26) A 15-µF capacitor is connected to a 50-V battery and becomes fully charged. The battery is
removed and a slab of dielectric that completely fills the space between the plates is inserted. If the
dielectric has a dielectric constant of 5.0, what is the voltage across the capacitor's plates after the
slab is inserted?
A) 2.0 V
B) 250 V
C) 10 V
D) 0.75 V
26)
3
NAME
Ch 18 Review
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) The total amount of charge that passes through a wire's full cross section at any point per unit of
time is referred to as
A) voltage.
B) electric potential.
C) wattage.
D) current.
1)
2) A coulomb per second is the same as
A) an ampere.
C) a volt-second.
2)
B) a watt.
D) a volt per second.
3) Car batteries are rated in "amp-hours." This is a measure of their
A) current.
B) charge.
C) power.
D) emf.
4) What is 1 equivalent to?
A) 1 V/A
D) 1 W/A
B) 1 V·A
C) 1 J/s
3)
4)
5) The resistance of a wire is
A) proportional to its length and inversely proportional to its cross-sectional area.
B) inversely proportional to its length and its cross-sectional area.
C) proportional to its length and its cross-sectional area.
D) inversely proportional to its length and proportional to its cross-sectional area.
5)
6) Consider two copper wires. One has twice the length of the other. How do the resistances of these
two wires compare?
A) Both wires have the same resistance.
B) The longer wire has twice the resistance of the shorter wire.
C) The longer wire has half the resistance of the shorter wire.
D) none of the given answers
6)
7) Consider two copper wires. One has twice the cross-sectional area of the other. How do the
resistances of these two wires compare?
A) The thicker wire has half the resistance of the shorter wire.
B) Both wires have the same resistance.
C) The thicker wire has twice the resistance of the shorter wire.
D) none of the given answers
7)
8) Consider two copper wires. One has twice the length and twice the cross-sectional area of the
other. How do the resistances of these two wires compare?
A) The longer wire has twice the resistance of the shorter wire.
B) The longer wire has four times the resistance of the shorter wire.
C) Both wires have the same resistance.
D) none of the given answers
8)
9) Materials in which the resistivity becomes essentially zero at very low temperatures are referred to
as
A) conductors.
B) superconductors.
C) semiconductors.
D) insulators.
9)
1
10) How much charge must pass by a point in 10 s for the current to be 0.50 A?
A) 5.0 C
B) 2.0 C
C) 20 C
10)
D) 0.050 C
11) A charge of 12 C passes through an electroplating apparatus in 2.0 min. What is the average
current?
A) 1.0 A
B) 6.0 A
C) 0.60 A
D) 0.10 A
11)
12) If 3.0 × 1015 electrons flow through a section of a wire of diameter 2.0 mm in 4.0 s, what is the
current in the wire?
A) 0.24 mA
B) 7.5 × 1014 A
C) 7.5 × 107 A
D) 0.12 mA
12)
13) A light bulb operating at 110 V draws 1.40 A of current. What is its resistance?
A) 109
B) 78.6
C) 12.7
D) 154
13)
14) What is the resistance of 1.0 m of no. 18 copper wire (diameter 0.40 in)? (The resistivity of copper is
1.68 × 10-8 ·m.)
A) 0.0021
B) 0.0012
C) 0.00012
D) 0.00021
14)
15) What length of copper wire (resistivity 1.68 × 10-8
resistance of 15 ?
A) 1.6 m
B) 16 mm
15)
·m) of diameter 0.15 mm is needed for a total
C) 16 m
D) 16 cm
16) A heavy bus bar is 20 cm long and of rectangular cross-section, 1.0 cm × 2.0 cm. What is the
voltage drop along its length when it carries 4000 A? (The resistivity of copper is 1.68 × 10-8
A) 0.34 V
B) 0.067 V
C) 0.67 V
D) 0.034 V
16)
·m.)
17) A toaster is rated 800 W at 120 V. What is the resistance of its heating element?
A) 16
B) 0.15
C) 6.7
D) 18
17)
18) A 200- resistor is rated at 1/4 W. What is the maximum current it can draw?
A) 0.035 A
B) 0.25 A
C) 50 A
D) 0.35 A
18)
19) A 200- resistor is rated at 1/4 W. What is the maximum voltage?
A) 7.1 V
B) 0.25 V
C) 0.71 V
19)
D) 50 V
20) How much does it cost to operate a 25-W soldering iron for 8.0 hours, if energy costs $0.08/kWh?
A) $0.16
B) $0.25
C) $0.016
D) $1.50
20)
21) How much energy does a 100-W light bulb use in 8.0 hours?
A) 13 kWh
B) 0.80 kWh
C) 0.0080 kWh
21)
D) 800 kWh
22) A motor that can do work at the rate of 2.0 hp has 60% efficiency. How much current does it draw
from a 120-V line? (1 hp = 746 W.)
A) 12 A
B) 17 A
C) 29 A
D) 21 A
22)
23) A 500-W device is connected to a 120-V ac power source. What peak current flows through this
device?
A) 170 A
B) 4.2 A
C) 120 A
D) 5.9 A
23)
2
NAME
Ch 19 Review
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Four resistors of 12, 3.0, 5.0, and 4.0 are connected in series. A 12-V battery is connected to the
combination. What is the current through the battery?
A) 0.50 A
B) 2.0 A
C) 1.5 A
D) 1.0 A
1)
2) Three resistors of 12, 12, and 6.0 are connected in parallel. A 12-V battery is connected to the
combination. What is the current through the 6.0- resistor?
A) 4.0 A
B) 3.0 A
C) 1.0 A
D) 2.0 A
2)
3) A 14-A current flows into a series combination of a 3.0- and a 4.0is the voltage drop across the 3.0- resistor?
A) 38 V
B) 42 V
C) 56 V
3)
resistor. What
D) 98 V
4) A 22-A current flows into a parallel combination of 4.0 , 6.0 , and 12
flows through the 12- resistor?
A) 18 A
B) 3.7 A
C) 11 A
resistors. What current
5) A 22-A current flows into a parallel combination of a 4.0- , 6.0- , and 12current flows through the 4.0- resistor?
A) 7.3 A
B) 3.7 A
C) 11 A
4)
D) 7.3 A
resistor. What
5)
D) 18 A
6) A 6.0- and a 12- resistor are connected in parallel to a 36-V battery. What power is dissipated
by the 6.0- resistor?
A) 24 W
B) 220 W
C) 490 W
D) 48 W
6)
7) The following three appliances are connected to a 120-V circuit: 1200-W toaster, 650-W coffee pot,
and 600-W microwave. If all were operated at the same time what total current would they draw?
A) 4.0 A
B) 10 A
C) 5.0 A
D) 20 A
7)
8) What is the maximum number of 100-W light bulbs you can connect in parallel in a 120-V circuit
without tripping a 20-A circuit breaker?
A) 17
B) 27
C) 24
D) 11
8)
9) A 2.0- resistor is in series with a parallel combination of 4.0
equivalent resistance of this combination?
A) 1.8
B) 2.7
C) 24
9)
, 6.0
, and 12
. What is the
D) 4.0
10) Three resistors of 4.0, 6.0, and 10.0 are connected in parallel. If the combination is connected in
series with a 12.0-V battery and a 2.0- resistor, what is the current through the 10.0- resistor?
A) 2.7 A
B) 0.59 A
C) 16.0 A
D) 11.2 A
1
10)
FIGURE 19-2
11) What is the total resistance of the circuit in Fig. 19-2?
A) 55
B) 80
C) 50
12) If E = 40 V, what is the voltage on R 1 in Fig. 19-2?
A) 20 V
11)
12)
B) 6.7 V
C) 10 V
13) If E = 20 V, what is the current through R 3 in Fig. 19-2?
A) 1.0 A
D) 35
B) 0.20 A
C) 4.0 A
D) 8.0 V
13)
D) 0.050 A
FIGURE 19-7
14) What current flows in the 12- resistor in Fig. 19-7?
A) 0.75 A
B) 1.0 A
C) 0.50 A
15) What current flows in the 18- resistor in Fig. 19-7?
A) 0.75 A
B) 1.0 A
C) 0.25 A
D) 0.25 A
D) 0.50 A
14)
15)
16) What current flows in the solid wire connecting the upper left and lower left corners?
A) 1.0 A
B) 0.75 A
C) 0.25 A
D) 0.50 A
16)
17) Four 16 µF capacitors are connected in series. The equivalent capacitance of this combination is
A) 64 µF.
B) 8.0 µF.
C) 16 µF.
D) 4.0 µF.
17)
18) A 1.0-µF and a 2.0-µF capacitor are connected in series across a 3.0-V battery. What is the voltage
across the 1.0-µF capacitor?
A) zero
B) 3.0 V
C) 1.0 V
D) 2.0 V
18)
2
19) 1.0 µF, 2.0 µF, and 3.0 µF capacitors are connected in parallel across a 24-V battery. How much
energy is stored in this combination when the capacitors are fully charged?
A) 4.8 mJ
B) 1.7 mJ
C) 7.1 mJ
D) 2.1 mJ
19)
20) Two capacitors of 6.00 µF and 8.00 µF are connected in parallel. The combination is then connected
in series with a 12.0-V battery and a 14.0-µF capacitor. What is the equivalent capacitance?
A) 7.00 µF
B) 14.0 µF
C) 8.00 µF
D) 6.00 µF
20)
21) Two capacitors of 6.00 µF and 8.00 µF are connected in parallel. The combination is then connected
in series with a 12.0-V battery and a 14.0-µF capacitor. What is the voltage across the 6.00-µF
capacitor?
A) 4.00 V
B) 5.00 V
C) 12.0 V
D) 6.00 V
21)
22) A 2.0-µF capacitor is charged through a 50-k
reach 90% of full charge?
A) 0.23 s
B) 2.3 s
22)
resistor. How long does it take for the capacitor to
C) 0.90 s
23) A 2.0-µF capacitor is charged to 12 V and then discharged through a 4.0 × 106
long will it take for the voltage across the capacitor to drop to 3.0 V?
A) 8.0 s
B) 24 s
C) 22 s
D) 2.2 s
resistor. How
D) 11 s
24) A 4.0-M resistor is connected in series with a 0.50-µF capacitor. The capacitor is initially
uncharged. The RC combination is charged by a 9.0-V battery. What is the change in voltage
between t = RC and t = 3RC?
A) 11 V
B) 2.9 V
C) 5.7 V
D) 7.6 V
3
23)
24)
NAME
Ch 20 Review
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) If a bar magnet is divided into two equal pieces,
A) two magnets result.
C) an electric field is created.
B) the magnet properties are destroyed.
D) the north and south poles are separated.
2) The Earth's geographic North Pole is magnetically a
A) north pole.
B) south pole.
1)
2)
3) Which of the following is correct?
A) When a current carrying wire is in your left hand, thumb in the direction of the current, your
fingers point in the direction of the magnetic field lines.
B) When a current carrying wire is in your right hand, thumb in the direction of the magnetic
field lines, your fingers point in the direction of the current.
C) When a current carrying wire is in your left hand, thumb in the direction of the magnetic field
lines, your fingers point in the direction of the current.
D) When a current carrying wire is in your right hand, thumb in the direction of the current,
your fingers point in the direction of the magnetic field lines.
3)
4) The force on a current-carrying wire in a magnetic field is the strongest when
A) the current is parallel to the field lines.
B) the current is at a 60° angle with respect to the field lines.
C) the current is at a 30° angle with respect to the field lines.
D) the current is perpendicular to the field lines.
4)
5) A wire carries a current of 10 A in a direction of 30° with respect to the direction of a 0.30-T
magnetic field. Find the magnitude of the magnetic force on a 0.50-m length of the wire.
A) 0.75 N
B) 1.5 N
C) 6.0 N
D) 3.0 N
5)
6) A thin copper rod 1.0 m long has a mass of 0.050 kg and is in a magnetic field of 0.10 T. What
minimum current in the rod is needed in order for the magnetic force to cancel the weight of the
rod?
A) 4.9 A
B) 9.8 A
C) 1.2 A
D) 2.5 A
6)
7) A proton moving at 4.0 × 104 m/s horizontally enters a region where a magnetic field of 0.13 T is
present, directed vertically downward. What force acts on the proton?
A) 1.4 × 10-16 N
B) zero
C) 5.2 × 10-16 N
D) 8.3 × 10-16 N
7)
8) A proton travels at a speed of 5.0 × 107 m/s through a 1.0-T magnetic field. What is the magnitude
of the magnetic force which acts on the proton if the angle between the proton's velocity and the
magnetic field vector is 30°?
A) 2.0 × 10-12 N
B) 4.0 × 10-14 N
C) 2.0 × 10-14 N
D) 4.0 × 10-12 N
8)
9) A high power line carrying 1000 A generates what magnetic field at the ground, 10 m away?
A) 2.0 × 10-5 T
B) 6.4 × 10-6 T
C) 4.7 × 10-6 T
D) 5.6 × 10-5 T
9)
1
10) Two long parallel wires carry currents of 20 A and 5.0 A in opposite directions. The wires are
separated by 0.20 m. What is the magnetic field midway between the two wires?
A) 5.0 × 10-5 T
B) 4.0 × 10-5 T
C) 3.0 × 10-5 T
D) 1.0 × 10-5 T
10)
11) Two long parallel wires carry currents of 20 A and 5.0 A in opposite directions. The wires are
separated by 0.20 m. At what point between the two wires are the contributions from the two wires
the same?
A) 0.12 m from the 20 A wire
B) 0.040 m from the 20 A wire
C) 0.080 m from the 20 A wire
D) 0.16 m from the 20 A wire
11)
12) What is the magnetic field at the center of a circular loop of wire of radius 4.0 cm when a current of
2.0 A flows in the wire?
A) 1.3 × 10-5 T
B) 3.1 × 10-5 T
C) 1.3 × 10-6 T
D) 3.1 × 10-6 T
12)
13) A solenoid with 500 turns is 0.10 m long and carries a current of 4.0 A. What strength of magnetic
field will it have at its center?
A) 13 mT
B) 3.1 mT
C) 6.2 mT
D) 25 mT
13)
14) How much current must pass through a 400 turn coil 4.0 cm long to generate a 1.0-T magnetic field
at the center?
A) 13 A
B) 40 A
C) 0.013 A
D) 80 A
14)
15) A circular loop of wire of cross-sectional area 0.12 m2 consists of 200 turns, each carrying 0.50 A. It
is placed in a magnetic field of 0.050 T oriented at 30° to the plane of the loop. What torque acts on
the loop?
A) 2.5 m·N
B) 0.25 m·N
C) 5.2 m·N
D) 0.52 m·N
15)
16) A proton is accelerated from rest through 500 V. It enters a magnetic field of 0.30 T oriented
perpendicular to its direction of motion. Determine the radius of the path it follows.
A) 1.1 cm
B) 11 cm
C) 1.1 mm
D) 1.1 m
16)
17) A proton travels through a potential of 1.0 kV and then moves into a magnetic field of 0.040 T.
What is the radius of the proton's resulting orbit?
A) 0.11 m
B) 0.17 m
C) 0.14 m
D) 0.080 m
17)
18) In a mass spectrometer, a single-charged particle (charge e) has a speed of 1.0 × 106 m/s and enters
a uniform magnetic field of 0.20 T. The radius of the circular orbit is 0.020 m. What is the mass of
the particle?
A) 3.1 × 10-31 kg
B) 3.2 × 10-28 kg
C) 6.4 × 10-28 kg
D) 1.7 × 10-27 kg
18)
19) At double the distance from a long current-carrying wire, the strength of the magnetic field
produced by that wire decreases to
A) 1/8 of its original value.
B) 1/2 of its original value.
C) 1/4 of its original value.
D) none of the given answers
19)
20) Two long parallel wires carry equal currents. The magnitude of the force between the wires is F.
The current in each wire is now doubled. What is the magnitude of the new force between the two
wires?
A) 2F
B) 4F
C) F/4
D) F/2
20)
2
21) A long straight wire carries current toward the east. A proton moves toward the east alongside and
just south of the wire. What is the direction of the force on the proton?
A) south
B) north
C) down
D) up
21)
22) The maximum torque on a current carrying loop occurs when the angle between the loop's
magnetic moment and the magnetic field vector is
A) 0°
B) 180°
C) 90°
D) none of the given answers
22)
23) An electron moving along the +x axis enters a region where there is a uniform magnetic field in the
+y direction. What is the direction of the magnetic force on the electron? (+x to right, +y up, and +z
out of the page.)
A) -z direction
B) +z direction
C) -y direction
D) -x direction
23)
24) When placed askew in a magnetic field, a current carrying loop that is free to rotate in any direction
will experience a torque until its magnetic moment vector
A) is at right angles to the magnetic field vector.
B) makes a 45° angle with the magnetic field vector.
C) is aligned with the magnetic field vector.
D) makes an angle of 270° with the magnetic field vector.
24)
25) A charged particle moves with a constant speed through a region where a uniform magnetic field is
present. If the magnetic field points straight upward, the magnetic force acting on this particle will
be maximum when the particle moves
A) upward at an angle of 45° above the horizontal.
B) straight upward.
C) straight downward.
D) in a plane parallel to the Earth's surface.
25)
26) The force on a current-carrying wire in a magnetic field is equal to zero when
A) the current is at a 30° angle with respect to the field lines.
B) the current is at a 60° angle with respect to the field lines.
C) the current is perpendicular to the field lines.
D) the current is parallel to the field lines.
26)
3
NAME
Ch 21 Review
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Doubling the number of loops of wire in a coil produces what kind of change on the induced emf,
assuming all other factors remain constant?
A) The induced emf is 4 times as much.
B) The induced emf is half as much.
C) The induced emf is twice times as much.
D) There is no change in the induced emf.
1)
2) Doubling the strength of the magnetic field through a loop of wire produces what kind of change
on the induced emf, assuming all other factors remain constant?
A) The induced emf is half as much.
B) The induced emf is twice as much.
C) The induced emf is 4 times as much.
D) There is no change in the induced emf.
2)
3) A circular coil lies flat on a horizontal table. A bar magnet is held above its center with its north
pole pointing down. The stationary magnet induces (when viewed from above)
A) a counterclockwise current in the coil.
B) no current in the coil.
C) a clockwise current in the coil.
D) a current whose direction cannot be determined from the information given.
3)
4) A circular coil lies flat on a horizontal table. A bar magnet is held above its center with its north
pole pointing down, and released. As it approaches the coil, the falling magnet induces (when
viewed from above)
A) a clockwise current in the coil.
B) no current in the coil.
C) a counterclockwise current in the coil.
D) a current whose direction cannot be determined from the information provided.
4)
5) A coil lies flat on a level table top in a region where the magnetic field vector points straight up.
The magnetic field suddenly grows stronger. When viewed from above, what is the direction of the
induced current in this coil as the field increases?
A) clockwise
B) clockwise initially, then counterclockwise before stopping
C) counterclockwise
D) There is no induced current in this coil.
5)
6) A long straight wire lies on a horizontal table and carries an ever-increasing current northward.
Two coils of wire lie flat on the table, one on either side of the wire. When viewed from above, the
induced current circles
A) counterclockwise in both coils.
B) counterclockwise in the east coil and clockwise in the west coil.
C) clockwise in the east coil and counterclockwise in the west coil.
D) clockwise in both coils.
6)
7) A wire moves across a magnetic field. The emf produced in the wire depends on
A) the orientation of the wire with respect to the magnetic field vector.
B) the length of the wire.
C) the strength of the magnetic field.
D) all of the given answers
7)
1
8) A resistor and an inductor are connected in series to a battery. The time constant for the circuit
represents the time required for the current to reach
A) 63% of the maximum current.
B) 25% of the maximum current.
C) 37% of the maximum current.
D) 75% of the maximum current.
8)
9) A transformer is a device that
A) operates only on DC.
B) operates only on AC.
C) operates on either DC or AC.
9)
10) A circular loop of radius 0.10 m is rotating in a uniform magnetic field of 0.20 T. Find the magnetic
flux through the loop when the plane of the loop and the magnetic field vector are parallel.
A) 5.5 × 10-3 T·m 2
B) 6.3 × 10-3 T·m 2
C) zero
D) 3.1 × 10-3 T·m 2
10)
11) A circular loop of radius 0.10 m is rotating in a uniform magnetic field of 0.20 T. Find the magnetic
flux through the loop when the plane of the loop and the magnetic field vector are at an angle of
30°.
A) 3.1 × 10-3 T·m 2
B) 5.5 × 10-3 T·m 2
C) zero
D) 6.3 × 10-3 T·m 2
11)
12) The cross-sectional area of an adjustable single loop is reduced from 1.0 m2 to 0.50 m2 in 0.10 s.
What is the average emf that is induced in this coil if it is in a region where B = 2.0 T upward, and
the coil's plane is perpendicular to B?
A) 20 V
B) 10 V
C) 15 V
D) 5 V
12)
13) A coil is wrapped with 200 turns of wire on a square frame with sides 18 cm. A uniform magnetic
field is applied perpendicular to the plane of the coil. If the field changes uniformly from 0.50 T to
0 in 8.0 s, find the average value of the induced emf.
A) 0.21 V
B) 2.1 mV
C) 0.41 V
D) 4.1 mV
13)
14) A square coil of wire with 15 turns and an area of 0.40 m2 is placed parallel to a magnetic field of
0.75 T. The coil is flipped so its plane is perpendicular to the magnetic field in 0.050 s. What is the
magnitude of the average induced emf?
A) 36 V
B) 90 V
C) 45 V
D) 6.0 V
14)
15) An AC generator consists of 100 turns of wire of area 0.090 m2 and total resistance 12 . The loops
rotate in a magnetic field of 0.50 T at a constant angular speed of 60 revolutions per second. Find
the maximum induced emf.
A) 3.4 kV
B) 0.27 kV
C) 0.54 kV
D) 1.7 kV
15)
16) Suppose that you wish to construct a simple AC generator with an output of 12 V maximum when
rotated at 60 Hz. A magnetic field of 0.050 T is available. If the area of the rotating coil is 100 cm2 ,
how many turns are needed?
A) 64
B) 128
C) 32
D) 16
16)
17) You are designing a generator with a maximum emf 8.0 V. If the generator coil has 200 turns and a
cross-sectional area of 0.030 m2 , what would be the frequency of the generator in a magnetic field
of 0.030 T?
A) 7.1 Hz
B) 7.5 Hz
C) 44 Hz
D) 8.0 Hz
17)
2
18) The windings of a DC motor have a resistance of 6.00 . The motor operates on 120 V AC, and
when running at full speed it generates a back emf of 105 V. What is the starting current of the
motor?
A) 37.5 A
B) 17.5 A
C) 20.0 A
D) 2.50 A
18)
19) A DC motor of internal resistance 6.0 is connected to a 24-V power supply. The operating
current is 1.0 A. What is the start-up current?
A) 4.0 A
B) 2.0 A
C) 1.0 A
D) 3.0 A
19)
20) A DC motor of internal resistance 6.0 is connected to a 24-V power supply. The operating
current is 1.0 A at full speed. What is the back emf when the motor is running at full speed?
A) 6.0 V
B) zero
C) 18 V
D) 24 V
20)
21) A DC motor of internal resistance 6.0 is connected to a 24-V power supply. The operating
current is 1.0 A at full speed. What is the back emf when the motor is running at half speed?
A) 24 V
B) 6.0 V
C) 18 V
D) 9.0 V
21)
22) A step-down transformer is needed to reduce a primary voltage of 120 V AC to 6.0V AC. What
turns ratio is required?
A) 10:1
B) 20:1
C) 1:20
D) 1:10
22)
23) 2.0 A in the 100-turn primary of a transformer causes 14 A to flow in the secondary. How many
turns are in the secondary?
A) 114
B) 14
C) 4
D) 700
23)
24) An transformer consists of a 500-turn primary coil and a 2000-turn secondary coil. If the current in
the secondary is 3.0 A, what is the current in the primary?
A) 12 A
B) 48 A
C) 1.3 A
D) 0.75 A
24)
25) The primary of a transformer has 100 turns and its secondary has 200 turns. If the power input to
the primary is 100 W, we can expect the power output of the secondary to be (neglecting frictional
losses)
A) 100 W.
B) 50 W.
C) 200 W.
D) none of the given answers
25)
26) A 4.0-mH coil carries a current of 5.0 A. How much energy is stored in the coil's magnetic field?
A) 10 mJ
B) 2.0 mJ
C) 20 mJ
D) none of the given answers
26)
27) What is the peak voltage in an AC circuit where the rms voltage is 120 V?
A) 170 V
B) 120 V
C) 84.8 V
D) none of the given answers
27)
28) A simple RL circuit contains a 6.0constant?
A) 0.33 s
C) 108 s
28)
resistor and an 18-H inductor. What is this circuit's time
B) 3.0 s
D) none of the given answers
29) A 150-W lamp is placed into a 120-V AC outlet. What is the peak current?
A) 0.80 A
B) 0.88 A
C) 1.77 A
3
D) 1.25 A
29)
30) A 150-W lamp is placed into a 120-V AC outlet. What is the resistance of the lamp?
A) 1.25
B) 96
C) 0.80
D) 48
30)
31) A 10- resistor is connected to a 120-V ac power supply. What is the peak current through the
resistor?
A) 12 A
B) 0.12 A
C) 17 A
D) 0.083 A
31)
4
Name
Ch 26 Review WS
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) If the velocity of your spaceship goes from 0.3 c to 0.6 c, then your mass will increase by
A) 19%.
B) 38%.
C) 200%.
D) 100%.
1)
2) What is the total energy of an electron moving with a speed of 0.95c?
A) 8.2 × 10-14 J
B) 1.1 × 10-13 J
C) 2.6 × 10-13 J
2)
D) 1.2 × 10-14 J
3) A fast spaceship is traveling with a speed of 0.80c. How fast would light travel from the headlights
of the ship relative to a stationary observer?
A) 1.0c
B) 0.80c
C) 1.8c
D) 0.20c
3)
4) The length of a spaceship is 10 m when it is at rest. If the spaceship travels by you with a speed of
0.70c, what length does it appear to you?
A) 5.5 m
B) 18 m
C) 7.1 m
D) 12 m
4)
5) A spaceship moves away from the Earth with a speed of 0.80c. The spaceship then fires a missile
with a speed of 0.50c relative to the spaceship. What is the velocity of the missile measured by
observers on the Earth if the missile is fired toward the Earth?
A) 0.93c
B) 1.3c
C) 0.30c
D) 0.50c
5)
6) The kinetic energy of a proton is 80% of its total energy. What is the momentum in kg·m/s of the
proton?
A) 2.5 × 10-19 kg·m/s
B) 5.0 × 10-18 kg·m/s
C) 2.5 × 10-18 kg·m/s
D) 5.0 × 10-19 kg·m/s
6)
7) How much mass is lost during a reaction in which 1.7 × 108 MeV of energy is released?
A) 5.7 × 10-9 kg
B) 3.0 × 10-22 kg
C) 1.8 × 10-8 kg
D) 1.9 × 10-17 kg
7)
8) The closest star to our solar system is Alpha Centauri, which is 4.30 light years away. A spaceship
with a constant speed of 0.800c relative to the Earth travels toward the star. How much time would
elapse on a clock on board the spaceship?
A) 5.15 y
B) 5.38 y
C) 4.40 y
D) 3.23 y
8)
9) One 20-year-old twin brother takes a space trip with a speed of 0.80c for 30 years according to a
clock on the spaceship. Upon returning to the Earth, what is his own age and the age of the
Earth-based twin brother?
A) 50; 70
B) 20; 30
C) 30; 50
D) 70; 90
9)
10) A spaceship moves away from the Earth with a speed of 0.80c. The spaceship then fires a missile
with a speed of 0.50c relative to the spaceship. What is the velocity of the missile measured by
observers on the Earth if the missile is fired away from the Earth?
A) 1.3c
B) 0.50c
C) 0.30c
D) 0.93c
10)
11) An electron is traveling at 0.85c. What is its mass? (The rest mass is 9.11 × 10-31 kg.)
A) 1.4 × 10-29 kg
B) 7.2 × 10-30 kg
C) 2.4 × 10-30 kg
D) 1.7 × 10-30 kg
11)
1
12) The amount of energy equivalent to two kilogram of mass at rest is
A) 9.0 × 1016 J.
B) 18 × 1016 J.
C) 3.0 × 108 J.
D) none of the given answers
12)
13) A spaceship takes a nonstop journey to a planet and returns in 10 hours according to a clock on the
spaceship. If the speed of the spaceship is 0.80c, how much time has elapsed on the Earth?
A) 7.0 h
B) 15 h
C) 17 h
D) 3.2 h
13)
14) How much energy would be released if 2.0 kg of material was lost during a reaction?
A) 4.7 × 10-8 J
B) 1.8 × 1017 J
C) 6.0 × 108 J
D) 1.5 × 1016 J
14)
15) What is the speed of a proton if its mass is twice its rest mass?
A) 0.50c
B) 0.73c
C) 0.87c
15)
D) 0.68c
16) The kinetic energy of a proton is 80% of its total energy. What is the speed of the proton?
A) 1.0c
B) 0.98c
C) 0.02c
D) 0.87c
16)
17) What energy is released (in MeV) during a reaction in which 1.67 × 10-25 kg of material is
converted to energy?
A) 5.0 × 10-14 MeV
B) 3.1 × 10-4 MeV
C) 9.4 × 104 MeV
D) 4.1 × 10-7 MeV
17)
18) A set of twins, Andrea and Courtney, are initially 10 years old. While Courtney remains on Earth,
Andrea rides on a space ship which travels away from Earth at a speed of 0.6c for five years (as
measured by Courtney), then turns around and comes back at 0.6c. When Andrea returns,
Courtney is 20 years old. How old is Andrea upon her return?
A) 18 years
B) 10 years
C) 12 years
D) 20 years
18)
19) How fast would a rocket ship have to move to contract to half of its proper length (as observed by a
stationary object)?
A) 0.78c
B) 0.50c
C) 0.65c
D) 0.87c
19)
20) A meter stick is moving toward you with a speed of 0.80c. What is its length?
A) 0.60 m
B) 1.0 m
C) 0.40 m
20)
D) zero
21) What is the momentum in kg·m/s of a proton when it is moving with a speed of 0.60c?
A) 1.5 × 10-19 kg·m/s
B) 1.2 × 10-19 kg·m/s
C) 3.8 × 10-19 kg·m/s
D) 3.0 × 10-19 kg·m/s
21)
22) During a reaction, 1.7 × 10-4 J of energy is released. What change of mass would cause this?
A) 1.9 × 10-21 kg
B) 5.1 × 10-4 kg
C) 1.5 × 10-13 kg
D) 4.8 × 10-18 kg
22)
23) An electron is accelerated through 100 kV. By what factor has its mass increased with respect to its
rest mass?
A) 1.20
B) 8.00
C) 1.55
D) 4.25
23)
2