Physics Midterm
An electron moving in the +y direction, at right angles to a magnetic field, experiences a magnetic force in the -x direction. The direction of the magnetic field is in the
+z direction
How to increase capacitance of parallel plate?
- increase the surface area - reduce the separation between the plate - use a dielectric material in between the plate which have higher dielectric breakdown strength
A proton moves at 7.50×107 m/a perpendicular to a magnetic field. The field causes the proton to travel in a circular path of radius 0.800 m. What is the field strength?
0.979 T
The maximum torque on a flat current-carrying loop occurs when the angle between the plane of the loop's area and the magnetic field vector is
0°
1 Ampere =
1 C/s
How many watts does a flashlight that has 6.00 x 102 C pass through it in 0.500h use if its voltage is 3.00 V?
1.00 W
What current flows through a 2.54cm diameter rod of pure silicon (resistivity 2.3 10^3 ohm) 20.0 cm long, when 1.00 x 10^3V is applied to it?
1.10 x 10^-3 A
A clock battery wears out after moving 18 x 10^3 C of charge through the clock at a rate of 1.5 mA. How long did the clock run?
1.2 x 10^7 s
The magnetic field at a distance of 2 cm from a long straight current-carrying wire is 4 μT. What is the magnetic field at a distance of 1 cm from this wire?
10 μT
What is the potential between two points situated 10 cm and 20 cm from a 3.0 μC point charge?
135 x 10^3 V
A pair of parallel plates, forming a capacitor, are charged. The plates are pulled apart to double the original separation, the charges on the plates remaining the same. What is the ratio of the final energy stored to the original energy stored?
2
The magnetic field at a distance of 2 cm from a long straight current-carrying wire is 4 μT. What is the magnetic field at a distance of 4 cm from this wire?
2 μT
The force of attraction that a -40.0 μC point charge exerts on a +108 μC point charge has magnitude 8.80 N. How far apart are these two charges? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2)
2.10 m
What is the equivalent resistance of a 36.0 ohm, a 50.0 ohm, and a 700 ohm resistor connected in parallel?
20 Ω
A charged particle is observed traveling in a circular path of radius R in a uniform magnetic field. If the particle were traveling twice as fast, the radius of the circular path would be
2R
How many volts are supplied to operate an indicator light on a DVD player that has a resistance of 140 Ω , given that 25.0 mA passes through it?
3.50 V
Two point charges are 4 cm apart. They are moved to a new separation of 2 cm. By what factor does the resulting mutual force between them change?
4
Inside a motor, 30.0A passes through a 250-turn circular loop that is 10.0 cm in radius. What is the magnetic field strength created at its center?
4.71 x 10^-2 T
When two long parallel wires carry unequal currents, the magnitude of the magnetic force that one wire exerts on the other is F. If the current in both wires is now doubled, what is the magnitude of the new magnetic force on each wire?
4F
A very long straight current-carrying wire produces a magnetic field of 20 mT at a distance d from the wire. To measure a field of 5 mT due to this wire, you would have to go to a distance from the wire of
4d
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°
Consider two copper wires of equal cross-sectional area. One wire has 3 times the length of the other. How do the resistivities of these two wires compare?
Both wires have the same resistivity; the longer wire has 3 times the resistance of the shorter wire.
The unit of capacitance, the farad, is dimensionally equivalent to which of the following?
C/V
A repelling force must occur between two charged objects under which conditions?
Charges are like signs
Two long parallel wires are placed side-by-side on a horizontal table and carry current in the same direction. The current in one wire is 20 A, and the current in the other wire is 5 A. If the magnetic force on the 20-A wire has magnitude F, what is the magnitude of the magnetic force on the 5-A wire? No external magnetic fields are present.
F
In a velocity selector consisting of perpendicular electric and magnetic fields, the speeds of the charged particles passing through the selector are increased or decreased until they are equal to the desired speed.
False
Three resistors connected in series each carry currents labeled I1, I2 and I3. Which of the following expresses the value of the total current IT in the system made up of the three resistors in series?
It = I₁ = I₂ = I₃
A soft magnetic material has which property?
It is easy to magnetize
Two long, parallel wires carry currents of different magnitudes. If the amount of current in one of the wires is doubled, what happens to the magnitude of the force that each wire exerts on the other?
It is increased by a factor of 2.
Two long, parallel wires carry currents of different magnitudes. If the current in one of the wires is doubled and the current in the other wire is halved, what happens to the magnitude of the magnetic force that each wire exerts on the other?
It stays the same.
What happens to the voltage in a series circuit?
It's shared
The unit of electrical potential, the volt, is dimensionally equivalent to:
J/C
Which is a unit of power?
J/s
Who was the first to determine the electron's charge?
Millikan
Will the electric field strength between two parallel conducting plates exceed the breakdown strength for air (3.0×106 V/m) if the plates are separated by 2.00 mm and a potential difference of 5.0×103 V is applied?
No
Two identical balls have the same amount of charge, but the charge on ball A is positive and the charge on ball B is negative. The balls are placed on a smooth, level, frictionless table whose top is an insulator. Which of the following is true?
None of the above is correct
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:
Oersted
Superconductivity was discovered by:
Onnes
A particle carrying a charge of +e travels in a circular path of radius R in a uniform magnetic field. If instead the particle carried a charge of +2e, the radius of the circular path would have been
R/2
If R1 < R2 < R3, and if these resistors are connected in series in a circuit, which one dissipates the greatest power?
R3
Three resistors with values R1, R2 and R3, respectively, are connected in parallel. Which of the following expresses the total resistance,RT, of the three resistors when connected in parallel?
Rt = (1/R₁ +1/R₂ + 1/R₃)⁻¹
Three resistors with values of R1, R2 and R3, respectively, are connected in series. Which of the following expresses the total resistance,RT, of the three resistors?
Rt = R₁ + R₂ + R₃
If R1 < R2 < R3, and if these resistors are connected in parallel in a circuit, which one has the highest current?
R₁
When unequal resistors are connected in parallel circuit,
The equivalent Resistance is less than the resistance of any of the resistors.
A wire lying in the plane of this page carries a current directly toward the top of the page. What is the direction of the magnetic force this current produces on an electron that is moving perpendicular to the page and outward from it on the left side of the wire?
The force is zero.
Which one of the following statements is correct?
The north pole of a magnet points towards Earth's geographic north pole.
A charged particle moving along the +x-axis enters a uniform magnetic field pointing along the +z-axis. Because of an electric field along the +y-axis, the charge particle does not change velocity. What is the sign of this particle?
The particle could be either positive or negative.
An object is hung using a metal spring. If now a current is passed through the spring, what will happen to this system?
The spring will contract, raising the weight.
Consider two copper wires with circular cross-sections and equal lengths. One wire has 3 times the diameter of the other. How do the resistances of these two wires compare?
The thicker wire has 1/9 the resistance of the thinner wire.
The unit of electric resistance, the ohm, is equivalent to which of the following?
V/A
The unit of electric current, the ampere, is equivalent to which of the following?
V/Ω
When current is flowing in a superconductor, which statement is not true?
a battery is needed to keep the current going
The magnetic pole of the Earth nearest the geographic North Pole corresponds to which of the following?
a magnetic South Pole
If a calculated quantity has units of N/Am , that quantity could be
a magnetic field.
If a calculated quantity has units of Ns/Cm , that quantity could be
a magnetic field.
Electrical charges and magnetic poles have many similarities, but one difference is:
a magnetic pole cannot be isolated
In which case does an electric field do positive work on a charged particle?
a negative charge moves opposite to the direction of the electric field
The size of the electric current in an electrical conductor is a function of which of the following?
all of the above are valid
Which of the following characteristics are held in common by both gravitational and electrostatic forces when dealing with either point masses or charges?
all of the above are valid
A charged particle moving along the +x-axis enters a uniform magnetic field pointing along the +z-axis. A uniform electric field is also present. Due to the combined effect of both fields, the particle does not change its velocity. What is the direction of the electric field?
along the +y-axis
An electron moving along the +x-axis enters a magnetic field. If the electron experiences a magnetic deflection in the -y direction, then the magnetic field must have a component
along the -z-axis
The term magnetic declination refers to which of the following?
angle between directions to true north and magnetic north
A free electron is in an electric field. With respect to the field, it experiences a force acting:
anti-parallel (opposite in direction)
If a charged particle is moving in a uniform magnetic field, its path can be:
any of the above
Consider an ideal solenoid of length L, N windings, and radius b (L is much longer than b). A current I is flowing through the wire windings. If the length of the solenoid becomes twice as long (to 2L), but all other quantities remained the same, the magnetic field inside the solenoid will
become one-half as strong as initially
A negatively-charged particle moves across a constant uniform magnetic field that is perpendicular to the velocity of the particle. The magnetic force on this particle
causes the particle to accelerate.
Kirchhoff's first rule (the junction rule) is an application of the conservation of
charge
Kirchhoff's second rule (the loop rule) is an application of conservation of
charge
Which of the following best characterizes electrical insulators?
charges on the surface don't move
A horizontal wire carries a current straight toward you. From your point of view, the magnetic field caused by this current
circles the wire in a counter-clockwise direction
The dip angle is:
close to or at zero near the equator.
A straight bar magnet is initially 4 cm long, with the north pole on the right and the south pole on the left. If you cut the magnet in half, the right half will
contain a north pole on the right and a south pole on the left.
Geophysicists today generally attribute the existence of the Earth's magnetic field to which of the following?
convection currents within the liquid interior
The basic function of an electromotive force in a circuit is to do which of the following?
convert some other form of energy into electrical
In the Millikan oil-drop experiment it was found that oil droplets:
could have positive, negative, or zero net charge
A long, straight wire carrying a current is placed along the y-axis. If the direction of the current is in the +y direction, what is the direction of the magnetic field due to this wire as you view it in such a way that the current is coming directly toward you?
counterclockwise, around the y-axis
Increasing the separation of the two charged parallel plates of a capacitor, which are disconnected from a battery, will produce what effect on the capacitor?
decrease capacitance
The magnetic field of the Earth is believed responsible for which of the following?
deflection of charged cosmic rays
The _________ is generally defined to be E0/E, or the ratio of the electric field in a vacuum to that in the dielectric material, and is intimately related to the polarizability of the material.
dielectric constant
The combination of two separated point charges of opposite sign but equal magnitude is called an electric:
dipole
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
When you double the number of windings in an ideal solenoid while keeping all other parameters (radius, length and current) fixed, the magnetic field at the center of the solenoid will
double
The electric field at point P due to a point charge Q a distance R away has magnitude E. In order to double the magnitude of the field at P, you could
double the charge to 2Q
Which process will double the power given off by a resistor?
doubling the current by making a resistance half as big
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
In a certain velocity selector consisting of perpendicular electric and magnetic fields, the charged particles move toward the east, and the magnetic field is directed to the north. What direction should the electric field point?
downward
When a superconductor's temperature drops below the critical temperature, its resistance:
drops to zero
If you were to cut a small permanent bar magnet in half
each piece would in itself be a smaller bar magnet with both north and south poles.
If you were to cut a small permanent bar magnet in half,
each piece would in itself be a smaller bar magnet with both north and south poles.
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
We observe that a moving charged particle experiences no magnetic force. From this we can definitely conclude that
either no magnetic field exists or the particle is moving parallel to the field.
Which of the following best characterizes electrical conductors?
electric charges move freely
The quantity of electrical potential, the volt, is dimensionally equivalent to:
electric field x distance
The beam of electrons that hits the screen of an oscilloscope is moved up and down by:
electrical charges on defelcting plates
Doug rubs a piece of fur on a hard rubber rod, giving the rod a negative charge. What happens?
electrons are added to the rod
When a glass rod is rubbed with silk, which of the following statements best describes what happens?
electrons are removed from the rod
Force between 2 parallel wires if current is the same direction in each
exert equal and opposite attractive forces
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 rfrom the wire center related to the magnitude of the field?
field inversely proportional to r
The number of electric field lines passing through a unit cross sectional area is indicative of:
field strength
A charged particle is injected into a uniform magnetic field such that its velocity vector is perpendicular to the magnetic field lines. Ignoring the particle's weight, the particle will
follow a circular path
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 applications where electrical shocks may be more likely, such as around water in kitchens and bathrooms, special outlets called GFI's are used. What does GFI stand for?
ground-fault interrupter
Ten coulombs of charge start from the negative terminal of a battery, flow through the battery and then leave the positive terminal through a wire, flow through a resistor and then return to the starting point on this closed circuit. In this complete process, the ten coulombs:
have no net change in potential energy
A wire is carrying current vertically downward. What is the direction of the force on this wire due to Earth's magnetic field?
horizontally towards the east
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 strongest when the particle moves
in a plane parallel to Earth's surface.
Inserting a dielectric material between two charged parallel conducting plates, originally separated by air and disconnected from a battery, will produce what effect on the capacitor?
increase capacitance
Increasing the voltage across the two plates of a capacitor will produce what effect on the capacitor?
increase charge
A resistor is made of a material that has a resistivity that is proportional to the current going through it. If the voltage across the resistor is doubled, what happens to the current through it?
increases by 2 1/2
The internal resistances of an ideal voltmeter and an ideal ammeter are respectively (ideal meaning the behavior of the system is not changed when using the meter):
infinite and zero
A positive charge is moving to the right and experiences an upward magnetic force, as shown in the figure. In which direction must the magnetic field have a component?
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
Two long parallel wires placed side-by-side on a horizontal table carry identical current straight toward you. From your point of view, the magnetic field at a point exactly between the two wires
is zero
Household 120-V outlets are made to accept three-pronged plugs. One of the prongs attaches to the "live" wire at 120 V, and another attaches to the "neutral" wire that is connected to ground. What is the round third prong for?
it connects the case of the appliance directly to ground for safety purposes
When a light bulb is turned on, its resistance increases until it reaches operating temperature. What happens to the current in the bulb as it is warming up?
it decreases
The resistivity of a material is doubled when heated a certain amount. What happens to the resistance of a resistor made of this material when heated the same amount.
it doubles
When an electromagnet has an iron core inserted, what happens to the strength of the magnet?
it increases
In a mass spectrometer, an ion will have a smaller radius for its circular path if:
its charge is greater
When a ferromagnetic material is placed in an external magnetic field, the net magnetic field of its magnetic domains becomes
larger
If two parallel, conducting plates have equal positive charge, the electric field lines will:
leave both plates and go to infinity
A charged particle that is moving in a static uniform magnetic field.
may experience a magnetic force, but its speed will not change
At which location will the electric field between the two parallel plates of a charged capacitor be the strongest in magnitude?
midway between the two plated nearest their center
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
If body M, with a positive charge, is used to charge body N by induction, what will be the nature of the charge left on the latter?
must be negative
When an electric current exists within a conducting wire, which of the following statements describes the condition of any accompanying electric field?
must be parallel to current flow
If body P, with a positive charge, is placed in contact with body Q (initially uncharged), what will be the nature of the charge left on Q?
must be positive
A superconducting wire's chief characteristic is which of the following?
no resistance
Consider some material that has been cooled until it has become a superconductor. If it is cooled even further its resistance will:
none of the above
If a certain resistor obeys Ohm's law, its resistance will change:
none of the above, since resistance is a constant for the given resistor
Materials having resistance changes as voltage or current varies are called:
nonohmic
There is a magnetic force on a particle. It is possible that the particle is:
not part of a wire
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
Household circuits are wired in ____.
parallel
Voltmeters are connected in _______ with whatever device's voltage is to be measured
parallel
An electron is moving to the right, as shown in the figure. Suddenly it encounters uniform magnetic field pointing out of the page. Which one of the three paths shown will it follow in the field?
path a
The electric field at the surface of a positively charged conductor has a direction characterized by which of the following?
perpendicular outward and away from the charge
The direction of the force on a current-carrying wire in a magnetic field is
perpendicular to both the current and the magnetic field.
Two long parallel wires placed side-by-side on a horizontal table carry identical size currents in opposite directions. The wire on your right carries current directly toward you, and the wire on your left carries current directly away from you. From your point of view, the magnetic field at a point exactly midway between the two wires
points downward.
An uncharged conductor is supported by an insulating stand. I pass a positively charged rod near the left end of the conductor, but do not touch it. The right end of the conductor will be:
positive
If the distance between two isolated parallel plates that are oppositely charged is doubled, the electric field between the plates is essentially unchanged. However, the:
potential difference between the plates will double
The magnetic domains in a non-magnetized piece of iron are characterized by which orientation?
random
Consider an ideal solenoid of length L, N windings, and radius b (L is much longer than b). A current I is flowing through the wire windings. If the radius of the solenoid is doubled to 2b, but all the other quantities remain the same, the magnetic field inside the solenoid will
remain the same
The electric field of a point charge has an inverse ____ behavior.
r²
A galvanometer can be used as a voltmeter by connecting it in __________ with a large resistance. The value of the resistance is determined by the maximum voltage to be measured
series
The temperature coefficient of resistivity is a quantity that is:
sometimes negative
A vertical wire carries a current vertically downward. To the east of this wire, the magnetic field points
south
A charge, +Q, is placed inside a balloon and the balloon is inflated. As the radius of the balloon r increases the number of field lines going through the surface of the balloon:
stays the same
What happens to the voltage in a parallel circuit?
stays the same
The path of a charged particle moving parallel to a uniform magnetic field will be a:
straight line
Which of the following locations has the smallest (in magnitude) magnetic declination?
the South Carolina-Georgia border
I wish to use a positively charged rod to charge a ball by induction. Which statement is correct?
the ball must be a conductor
A light bulb with a tungsten filament is attached to a source of variable voltage. As the voltage is increased on the bulb,
the bulb's resistance increases
How can a charged object attract an uncharged object made of non-conducting material?
the charges in the uncharged object can becomes polarized
A current in a solenoid coil creates a magnetic field inside that coil. The field strength is directly proportional to:
the current
The magnetic force on a current-carrying wire in a magnetic field is the strongest when
the current is perpendicular to the magnetic field lines.
Three resistors, each with resistance R1, are in series in a circuit. They are replaced by one equivalent resistor, R. Comparing this resistor to the first resistor of the initial circuit, which of the following is true?
the current through R equals the current through R₁
If a conductor is in electrostatic equilibrium near an electrical charge:
the electric field inside the conductor must be zero
The Millikan oil-drop experiment demonstrated that:
the electronic charge is quantized
Doubling the voltage across a parallel plate capacitor does not double which of the following?
the energy stored
Consider two charged spheres, one with charge +2 C and the other with -2 C. A proton (a positively charged particle) is at the point halfway between the spheres. What is not zero?
the force of the proton
If a charge +Q is placed inside a hollow isolated conductor that is originally neutral and the charge does not touch that conductor at any time:
the outside surface of the counter will become positively charged
There is a hollow, conducting, uncharged sphere with a negative charge inside the sphere. Consider the electrical potential at the inner and outer surfaces of the sphere. Which of the following is true?
the potentials on both surfaces are equal but not zero
Relative distribution of charge density on the surface of a conducting solid depends on:
the shape of the conductor
A flat circular wire loop lies in a horizontal plane on a table and carries current in a counterclockwise direction when viewed from above. At this point, the earth's magnetic field points to the north and dips below the horizontal. Which side of the coil tends to lift off of the table due to the magnetic torque on the loop?
the south side
When you flip a switch to turn on a light, the delay before the light turns on is determined by:
the speed of the electric field moving in the wire
The electric field associated with a uniformly charged hollow metallic sphere is the greatest at:
the sphere's outer surface
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
Three resistors, each with resistance R1, are in parallel in a circuit. They are replaced by one equivalent resistor, R. Compare this resistor to the first resistor of the initial circuit. Which of the following statements is true?
the voltage across R equals the voltage across R₁
Which voltage is not caused by a source of emf?
the voltage across a charged capacitor
Two long parallel wires are placed side-by-side on a horizontal table. If the wires carry current in the same direction,
the wires pull toward each other.
Two long parallel wires are placed side-by-side on a horizontal table. If the wires carry current in opposite directions,
the wires push away from 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
When charging two objects by rubbing them together:
they must be made of different material
If one doubles the emfs in a circuit and doubles the resistances in the circuit at the same time, what happens to the currents through the resistors? Assume there are only emfs and resistors in the circuit.
they stay the same
A proton has an initial velocity to the south but is observed to curve upward as the result of a magnetic field. This magnetic field must have a component
to the east.
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
An electron has an initial velocity to the south but is observed to curve upward as the result of a magnetic field. This magnetic field must have a component
to the west.
A long, straight, horizontal 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 magnetic force on the proton?
toward the north
At a particular instant, a proton moves towards the east in a uniform magnetic field that is directed straight downward. The magnetic force that acts on it is
toward the north
At a particular instant, a proton moves toward the east in a uniform magnetic field that is directed straight downward. The magnetic force that acts on it is
toward the north.
A long, straight, horizontal wire carries current toward the east. An electron moves toward the east alongside and just south of the wire. What is the direction of the magnetic force on the electron?
toward the south
At a particular instant, an electron moves toward the east in a uniform magnetic field that is directed straight downward. The magnetic force that acts on it is
toward the south.
After landing on an unexplored Klingon planet, Spock tests for the direction of the magnetic field by firing a beam of electrons in various directions and by recording the following observations: Electrons moving upward feel a magnetic force in the northwest direction. Electrons moving horizontally toward the north are pushed downward. Electrons moving horizontally toward the southeast are pushed upward. Mr. Spock therefore concludes that the magnetic field at this landing site is in which direction?
toward the southwest
A vertical wire carries a current straight up in a region where the magnetic field vector points toward the north. What is the direction of the magnetic force on this wire?
toward the west
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 x 10^-4 T. What is the direction of the force on the wire?
towards the Earth's surface
A proton, moving north, enters a magnetic field. Because of this field, the proton curves downward. We may conclude that the magnetic field must have a component
towards the east
An electron, moving west, enters a magnetic field. Because of this field the electron curves upward. We may conclude that the magnetic field must have a component
towards the north.
A proton, moving east, enters a magnetic field. Because of this magnetic field the proton curves downward. We may conclude that the magnetic field must have a component
towards the south.
A proton, moving west, enters a magnetic field. Because of this magnetic field the proton curves upward. We may conclude that the magnetic field must have a component
towards the south.
An electron, moving south, enters a magnetic field. Because of this field, the electron curves upward. We may conclude that the magnetic field must have a component
towards the west
Which is not a force?
voltage
A proton is to orbit Earth at the equator using Earth's magnetic field to supply part of the necessary centripetal force. In what direction should the proton move?
westward
At what point is the charge per unit area greatest on the surface of an irregularly shaped conducting solid?
where curvature is greatest
An electron which moves with a speed of 3.0 x 10^4 m/s parallel to a uniform magnetic field of 0.40 T experiences a force of what magnitude? (e = 1.6 x 10^-19 C)
zero
The temperature coefficient of resistivity for a "perfect" ohmic material would be:
zero
There is a current I flowing in a clockwise direction in a square loop of wire that is in the plane of the paper. If the magnetic field B is toward the right, and if each side of the loop has length L, then the net magnetic force acting on the loop is
zero
If a calculated quantity has units of T ∙ m/A, that quantity could be
μ0
Three resistors connected in series have individual voltages labeled ∆V1, ∆V2 and ∆V3, respectively. Which of the following expresses the value of the total voltage ∆VT taken over the three resistors together?
∆Vt = ∆V1 +∆V2 +∆V3
Three resistors connected in parallel have the individual voltages labeled ∆V1, ∆V2 and ∆V3, respectively. Which of the following expresses the total voltage ∆VT across the three resistors when connected in this manner?
∆Vt = ∆V1 = ∆V2 = ∆V3
