University Physics II Midterm 2017 Multiple Choice
In the figure in question 34, which of the following relations is true? A.) I₁+I₂+I₃=0 B.) I₁+I₂-I₃=0 C.) I₁-I₂+I₃=0 D.) I₁-I₂-I₃=0 E.) -I₁+I₂+I₃=0
A.) I₁+I₂+I₃=0
A loop of wire is rotated about a diameter (which is perpendicular to a given magnetic field). In one revolution the induced current in the loop reverses direction how many times? A.) 0 B.) 3 C.) 1 D.) 4 E.) 2
E.) 2
Electromagnetic radiation of wavelength 3.5 meters is which type? A.) visible B.) AM-radio C.) ultraviolet D.) microwaves E.) FM-radio
E.) FM-radio
The lamps in a string of Christmas tree lights are connected in parallel. What happens if one lamp burns out? (Assume negligible resistance in the wires leading to the lamps). A.) The brightness of the lamps will not change appreciably. B.) The other lamps get dimmer equally C.) The other lamps get brighter equally D.) The other lamps get dimmer, but some get dimmer than others. E.) The other lamps get brighter, but some get brighter than others.
A.) The brightness of the lamps will not change appreciably.
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 twice as much B.) The induced emf is √2 times as much C.) The induced emf is 3 times as much D.) There is no change in the induced emf E.) The induced emf is 4 times as much
A.) The induced emf is twice as much
Alternating current and voltage (AC), rather than direct current and voltage (DC), are used for domestic electrical power. The reason for this based on one of the following physical principles. Which one? A.) When the number of magnetic field lines passing through a circuit changes, a voltage is generated in the circuit. B.) When a current flows through a resistance, heat is generated. C.) Opposite electric charges attract each other, and like charges repel each other. D.) When a current flows through a wire, a magnetic field is created. E.) When a current-carrying wire is placed in a magnetic field, it may experience a force if properly oriented.
A.) When the number of magnetic field lines passing through a circuit changes, a voltage is generated in the circuit.
Consider a capacitor connected across the AC supply. The current through the capacitor will _____ as the capacitance is increased. A.) decrease B.) increase C.) remain constant
A.) decrease
A negative charge, if free, tries to move ______. A.) from low potential to high potential B.) from high potential to low potential C.) away from infinity D.) towards infinity
A.) from low potential to high potential
In a pair of accelerating plates, such as found inside a CRT, the electrons are emitted _____ A.) from the cathode which is negative, toward the anode which is positive. B.) from the anode which is negative, toward the cathode which is positive. C.) from the cathode which is positive, toward the anode which is positive. D.) from the anode which is positive, toward the cathode which is negative.
A.) from the cathode which is negative, toward the anode which is positive.
If the frequency of the AC voltage across the inductor is doubled, the inductive resistance of that inductor ______. A.) increases to twice its original value B.) decreases to one-fourth its original value C.) decreases to one-half its original value D.) increases to 4 times its original value
A.) increases to twice its original value
A "blown" fuse has ______. A.) infinite (very large) resistance B.) moderate resistance C.) zero resistance
A.) infinite (very large) resistance
A charged particle moving along a direction perpendicular to the plane of a loop of current-carrying wire, and which passes through the loop's center, will experience _____. A.) no magnetic force B.) a magnetic torque C.) a magnetic force perpendicular to its velocity D.) a magnetic force parallel to the loop axis
A.) no magnetic force
What is the unit for the quantity RC? A.) seconds B.) ohms C.) volt-Ampere/ohm D.) meters E.) kg
A.) seconds
Consider an RLC circuit that is driven by an AC applied voltage. At resonance, ________. A.) the current is in phase with the driving voltage. B.) the peak voltage across the inductor is greater than the peak voltage across the capacitor. C.) the peak voltage across the resistor is equal to the peak voltage across the inductor. D.) the peak voltage across the capacitor is greater than the peak the voltage across the inductor.
A.) the current is in phase with the driving voltage.
Consider an RLC series circuit. The impedance of the circuit increases if Xc increases. A.) true only if XL is less than or equal to Xc B.) always true C.) true only if XL is greater than or equal to Xc D.) never true
A.) true only if XL is less than or equal to Xc
A resistor and a capacitor are connected in a series to an ideal battery of constant terminal voltage. When this system reaches its steady-stage, the voltage across the resistor is ________. A.) zero B.) less than the battery's terminal voltage, but greater than zero. C.) greater than the battery's terminal voltage. D.) equal to the battery's terminal voltage.
A.) zero
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 four times the resistance of the shorter wire B.) Both wires have the same resistance C.) The shorter wire has twice the resistance of the longer wire. D.) The shorter wire has four times the resistance of the longer wire. E.) The longer wire has twice the resistance of the shorter wire
B.) Both wires have the same resistance
A battery charges a parallel-plate capacitor fully and then is removed. The plates are immediately pulled apart. (With the battery disconnected, the amount of charge on the plates remains constant). What happens to the potential difference between the plates as they are being separated? A.) It remains constant B.) It increases C.) It decreases D.) There is no way to tell from the information given/.
B.) It increases
A bar magnet is dropped, N pole down, so it falls through a horizontal loop of wire. As it approaches the loop, the induced current is ______. A.) clockwise B.) counterclockwise C.) zero
B.) counterclockwise
A battery acquires and stores ______. A.) potential B.) energy, charge, and potential C.) charge D.) energy E.) charge and potential, but not energy
B.) energy, charge, and potential
Capacitors connected in series always have ______ total capacitance than any of the individual capacities. A.) the same B.) less C.) not enough information given D.) more
B.) less
A wire lying in the plane of the page carries a current toward the bottom of the page, as shown Figure: I is pointing to the bottom of the page. The electron is moving towards the left side of the page. What is the direction of the magnetic force it produces on an electron that is moving toward the wire, also in the plane of the page, from your right? A.) toward the top of the page B.) toward the bottom of the page C.) perpendicular to the page and away from you D.) zero E.) perpendicular to the page and towards you
B.) toward the bottom of the page
A charged particle is observed traveling in a circular path in a uniform magnetic field. If the particle had been traveling twice as fast, the radius of the circular path would be _____. A.) four times the original radius B.) twice the original radius C.) one-fourth the original radius D.) one-half the original radius E.) 1/√2 times the original radius
B.) twice the original radius
One side of a normal outlet is a 120 V AC, the other side is at ______. A.) 240 V B.) +120 V AC C.) 0 V D.) 120√2 V AC E.) -120 V AC
C.) 0 V
Which of the following will increase the capacitance of a parallel plate capacitor? A.) an increase in the potential difference between the plates. B.) none of the above C.) an increase in the plate area and a decreases in the plate separation D.) a decrease in the potential difference between the plates E.) a decrease in the plate area and an increase in the plate separation
C.) an increase in the plate area and a decreases in the plate separation
Lenz's Law is a consequence of the law of conservation of ______. A.) mass B.) charge C.) energy D.) momentum E.) electric field
C.) energy
The dedicated 3rd wire on a 3 prong plug is connected to ______. A.) a ground fault interrupter B.) the "hot" wire C.) ground D.) a fuse
C.) ground
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.) straight upward B.) upward at an angle of 45º above the horizontal C.) horizontally D.) straight downward
C.) horizontally
For an electron moving in a direction opposite to the electric field, _______. A.) its potential energy increases and its electric potential decreases B.) both its potential energy and its electiric potential remain constant C.) its potential energy decreases and its electric potential increases D.) its potential energy increases and its electric potential increases E.) its potential energy decreases and its electric potential decreases.
C.) its potential energy decreases and its electric potential increases
In a series RLC circuit the total impedance, ________. A.) always exceeds R B.) equals R + XL +Xc C.) never is less than R D.) never exceeds R
C.) never is less than R
A mass spectrometer needs _______. A.) only a magnetic field B.) a perpendicular gravitational field C.) perpendicular magnetic and electric fields D.) only an electric field E.) colinear magnetic and electric fields
C.) perpendicular magnetic and electric fields
The resistance of an object is defined as _______. A.) (length)/(resistivity)(cross-sectional area) B.) (current)/(voltage) C.) (voltage)(current) D.) (voltage)/(current) E.) (length)(resistivity)(cross-sectional)
D.) (voltage)/(current)
At double the distance from a long current-carrying wire, the strength of the magnetic field produced by that wire decreases to _______. A.) √2/3 of its original value B.) 1/4 of its original value C.) 1/8 of its original value D.) 1/2 of its original value E.) 1/√2 of its original value
D.) 1/2 of its original value
A voltage reading is obtained by placing a voltmeter across a resistor. What happens to the total current flowing in the circuit as a result of this action? A.) The current does not change B.) The current decreases C.) The current increases if the meter's internal resistance is less than the original resistance in the circuit and decreases if its internal resistance is greater than the circuit's original resistance. D.) The current increases
D.) The current increases
A coil lies flat on a table top in a region where the magnetic field vanishes suddenly. When viewed from above, what is the sense of the induced current this coil as the field fades? A.) The induced current flows clockwise B.) The current flows clockwise initially, and then it flows counterclockwise before stopping. C.) There is no induced current in this coil. D.) The induced current flows counterclockwise.
D.) The induced current flows counterclockwise.
When two or more resistors are connected in parallel to a battery, _______. A.) the equivalent resistance of the combination is less than the resistance of any one of the resistors B.) the total current flowing from the battery C.) the voltage across each resistor is the same D.) all of the other choices are true
D.) all of the other choices are true
Kirchhoff's junction rule is an example of ______ A.) conservation of energy and momentum B.) conservation of momentum C.) conservation of energy D.) conservation of charge
D.) conservation of charge
A horizontal metal bar rotates at a constant angular velocity w about a vertical axis through one of its ends while in a constant magnetic field B that is directed down. The emf induced between the two ends of the bar is ______. A.) variable with a maximum of Bω² B.) constant and proportional to the product Bω² C.) variable with a maximum of Bω² D.) constant and proportional to the product of Bω² E.) constant and proportional to the product of B²ω²
D.) constant and proportional to the product of Bω²
Consider a magnetic field pointing out of this page, as shown in the figure. An electron moving on the page toward the right will _____. A.) curve downward (path c) B.) speed up C.) continue straight ahead (path b) D.) curve upward (path a) E.) slow down
D.) curve upward (path a)
As more resistors are added in series to a constant voltage source (zero internal resistance), the power supplied by the source _____. A.) increases for a time and then starts to decrease B.) does not change C.) increases D.) decreases
D.) decreases
An ideal ammeter should _______. A.) consist of a galvanometer in series with a large resistor B.) have a high coil resistance C.) introduce a very large series resistance into the circuit whose current is to be measured D.) introduce a very small resistance into the circuit whose current is to be measured.
D.) introduce a very small resistance into the circuit whose current is to be measured.
Electric Potential Energy per unit charge is called ______. A.) power B.) dielectric constant C.) electric field D.) potential E.) eV
D.) potential
The power factor of an RLC circuit is defined as cos∅ = R/Z, but the phase angle can also be calculated from _____. A.) sin∅ = Z(XL-Xc) B.) sin∅ = RZ/(XL-Xc) C.) sin∅ = (XL-Xc)/RZ D.) sin∅ = (XL-Xc)/Z
D.) sin∅ = (XL-Xc)/Z
When resistors are connected series, _______. A.) the total effective resistance is reduced B.) the potential difference across each is the same C.) the same power is dissipated in each one D.) the current flowing in each is the same.
D.) the current flowing in each is the same.
A lightbulb is plugged into a household outlet, and one of the wires leading to it is wound into a coil. Now a slug of iron is slid into the coil. What effect will this have? A.) This will have no effect on the brightness of the lamp. B.) The lamp will dim because the energy will now be dissipated in the iron. C.) This will not affect the lamp's brightness because the coil shift the phase, but not the magnitude, of the current the lamp. D.) The lamp will be get brighter because there will be an induced emf that will drive more current through the lamp. E.) The lamp will dim because a back emf will be produced by the coil, and this will reduce the current flowing in the coil and the lamp.
E.) The lamp will dim because a back emf will be produced by the coil, and this will reduce the current flowing in the coil and the lamp.
A vertical wire carries a current straight up in a region where the magnetic field vector points due North. What is the direction of the resulting force on this current? A.) North B.) East C.) downward D.) South E.) West
E.) West
If the inductance and the capacitance both double in an LRC series circuit, the resonant frequency of that circuit will _______. A.) decrease to one-eighth its original value B.) decrease to one-fourth its original value C.) increase to twice its original value D.) increase to four times its original value E.) decrease to one-half its original value
E.) decrease to one-half its original value
A charged particle moves and experiences no magnetic force. From this we can conclude that ______. A.) no magnetic field exists in that region of space. B.) the particle is moving parallel to the magnetic C.) the particle must be massive. D,) the particle is moving at right angles to the magnetic field. E.) either no magnetic field exists or the particle is moving parallel to the field.
E.) either no magnetic field exists or the particle is moving parallel to the field.
A proton, moving in a uniform field, moves in a circle perpendicular to the field. If the proton's speed tripled, its time to go around its circular path would be ________. A.) one third B.) double C.) triple D.) one half E.) the same
E.) the same
If you connect two identical storage batteries together in parallel, and place them in a circuit, the combination will provide _______. A.) half the voltage and twice the total charge that one battery would B.) twice the voltage and the same total charge that one battery would C.) twice the voltage and twice the total charge that one batter would D.) half the voltage and half the total charge that one battery would E.) the same voltage and twice the total charge that one battery would.
E.) the same voltage and twice the total charge that one battery would.
