GenPhysTwo
In the figure, charge q1 = 3.1 x 10^-6 C is placed at the origin and charge q2 = -8.7 x 10^-6 C is placed on the x-axis, at x = -0.20 m. Where along the x-axis can a third charge Q = -8.3 µC be placed such that the resultant force on this third charge is zero?
0.30
An electron is bound in an infinite well (a box) of width 0.10 nm. If the electron is initially in the n = 8 state and falls to the n = 7 state, find the wavelength of the emitted photon.
2.2 nm
A metal surface has a work function of 1.50 eV. Calculate the maximum kinetic energy, in eV, of electrons ejected from this surface by electromagnetic radiation of wavelength 311 nm.
2.50 eV
A long straight wire on the z-axis carries a current of 6.0 A in the positive direction. A circular loop in the xy-plane, of radius 10 cm, carries a 1.0-A current, as shown in the figure. Point P, at the center of the loop, is 25 cm from the z-axis. An electron is projected from P with a velocity of 1.0 x 10^6 m/s in the negative x-direction. What is the y component of the force on the electron? A) zero B) -1.0 x 10^-18 N C) +2.0 x 10^-18 N D) -2.0 x 10^-18 N E) +1.0 x 10^-18 N
B) -1.0 x 10^-18 N
An electric device delivers a current of 5.0 A to a device. How many electrons flow through this device in 10 s? A) 2.0 B) 0.20 C) 31 x 10^20 D) 20 E) 3.1 x 10^20
E) 3.1 x 10^20
In a particular case of Compton scattering, a photon collides with a free electron and scatters backwards. The wavelength after the collision is exactly double the wavelength before the collision. What is the wavelength of the incident photon?
E) 4.8 pm
For a 93-41Nb atom, the number of protons, neutrons, and electrons in the atom is
E) 41, 52, 41
How fast must a hydrogen atom be traveling for its kinetic energy to be just enough to excite the ground-state atom to its first excited state in a collision?
E) 44.2 km/s
A diffraction grating has 300 lines per mm. If light of wavelength 630 nm is sent through this grating, what is the highest order maximum that will appear?
E) 5
A double-convex thin lens is made of glass with an index of refraction of 1.52. The radii of curvature of the faces of the lens are 60 cm and 72 cm. What is the focal length of the lens?
E) 63 cm
The smallest kinetic energy that an electron in a box (an infinite well) can have is zero. A) True B) False
B) False
Two concentric conducting spherical shells produce a radially outward electric field of magnitude 49,000 N/C at a point 4.10 m from the center of the shells. The outer surface of the larger shell has a radius of 3.75 m. If the inner shell contains an excess charge of -5.30 µC, find the amount of charge on the outer surface of the larger shell.
91.6 µC
For the missing product X in the reaction neutron + 235-92U --> 141-56Ba + X + 3 neutrons determine the atomic mass and atomic number of X, and write X in the standard form. It is NOT necessary to identify which atom X is.
A = 92 Z = 36 92-36X
The square of the wave function of a particle |(wave function(x))|^2, gives the probability of finding the particle at the point x. A) True B) False
B) False
A charge Q = -820 nC is uniformly distributed on a ring of 2.4 m radius. A point charge q = +530 nC is fixed at the center of the ring. Points A and B are located on the axis of the ring, as shown in the figure. What is the minimum work that an external force must do to transport an electron from B to A? A) -8.7 x 10^-17 J B) +8.7 x 10^-17 J C) +7.2 x 10^-18 J D) -7.2 x 10^-18 J E) +1.0 x 10^-16 J
A) -8.7 x 10^-17 J
Polarized light passes through a polarizer. If the electric vector of the polarized light is horizontal what, in terms of the initial intensity I, is the intensity of the light that passes through a polarizer if the polarizer is tilted 22.5º from the horizontal? A) 0.854I B) 0.191I C) 0.147I D) 0.011I
A) 0.854I
The current supplied by a battery as a function of time is I(t) = (0.88A)e^(-t/6.0h). What is the total number of electrons transported from the positive electrode to the negative electrode from the time the battery is first used until it is essentially dead? A) 1.2 x 10^23 B) 4.4 x 10^22 C) 3.3 x 10^19 D) 5.3 x 10^23
A) 1.2 x 10^23
A coil of 160 turns and area 0.20 m^2 is placed with its axis parallel to a magnetic field of initial magnitude 0.40 T. The magnetic field changes uniformly from 0.40 T in the +x direction to 0.40 T in the -x direction in 2.0 s. If the resistance of the coil is 16 ohms, at what rate is power generated in the coil? A) 10 W B) 15 W C) 5.0 W D) 25 W E) 20 W
A) 10 W
An infinitely long nonconducting cylinder of radius R=2.00 cm carries a uniform volume charge density of 18.0 uC/m^3. Calculate the electric field at distance r=1.00 cm from the axis of the cylinder. A) 10.2 x 10^3 N/C B) 2.50 x 10^3 N/C C) 2.00 x 10^3 N/C D) zero E) 5.10 x 10^3 N/C
A) 10.2 x 10^3 N/C
A series LRC circuit consists of a 100-Ω resistor, a 0.100 µF capacitor and a 2.00-mH inductor connected across a 120-V rms ac voltage source operating at 1000/π. At what frequency will this circuit be in resonance? A) 11.3 kHz B) 22.5 kHz C) 70.7 kHz D) 35.3 kHz E) 17.9 kHz
A) 11.3 kHz
If the electric potential in a region is given by V(x) = 6/x^2, the x component of the electric field in that region is A) 12x^-3 B) -12x^-3 C) 12x D) 6x E) -6x
A) 12x^-3
A very small object carrying -6.0 uC of charge is attracted to a large, well-anchored, positively charged object. How much kinetic energy does the negatively charged object gain if the potential difference through which it moves is 3.0 mV? A) 18 nJ B) 0.50 kJ C) 6.0 uJ D) 0.50 J
A) 18 nJ
In the figure, the orientation of the transmission axis for each of three polarizing sheets is labeled relative to the vertical direction. A beam of light, polarized in the vertical direction, is incident on the first polarized with an intensity of 1000 W/m^2. What is the intensity of the beam after it has passed through the three polarizing sheets when ø1 = 30º, ø2 = 30º, and ø3 = 60º? A) 563 W/m^2 B) 316 W/m^2 C) 433 W/m^2 D) 141 W/m^2 E) 188 W/m^2
A) 563 W/m^2
Given that the wavelengths of visible light range from 400 nm to 700 nm, what is the highest frequency of visible light? A) 7.5 x 10^14 Hz B) 3.1 x 10^8 Hz C) 2.3 x 10^20 Hz D) 4.3 x 10^14 Hz E) 5.0 x 10^8 Hz
A) 7.5 x 10^14 Hz
Thirteen resistors are connected across points A and B as shown in the figure. If all the resistors are accurate to 2 significant figures, what is the equivalent resistance between points A and B? A) 8.0 ohm B) 6.0 ohm C) 12 ohm D) 4.0 ohm E) 10 ohm
A) 8.0 ohm
In the circuit shown in the figure, all the lightbulbs are identical. Which of the following is the correct ranking of the brightness of the bulbs? A) A is the brightest, and B and C have equal brightness but less than A B) A is brightest, C is dimmest, and B is in between C) B and C have equal brightness, and A is the dimmest D) A and B have equal brightness, and C is the dimmest E) All three bulbs have the same brightness
A) A is the brightest, and B and C have equal brightness but less than A
A capacitor is charging in a simple RC circuit with a dc battery. Which one of the following statements about this capacitor is accurate? A) There is a magnetic field between the capacitor plates, even though no charge travels between them, because the electric flux between the plates is changing. B)There is a magnetic field between the capacitor plates, even though no charge travels between them, because the magnetic flux between the plates is changing. C) There is a magnetic field between the capacitor plates because charge travels between the plates by jumping from one plate to the other. D) There is no magnetic field between the capacitor plates because no charge travels between the plates. E) The magnetic field between the capacitor plates is increasing with time because the charge on the plates is increasing.
A) There is a magnetic field between the capacitor plates, even though no charge travels between them, because the electric flux between the plates is changing.
An electron is initially moving to the right when it enters a uniform electric field directed upwards. Which trajectory shown below will the electron follow? A) Trajectory Z B) Trajectory W C) Trajectory Y D) Trajectory X
A) Trajectory Z
If the electric potential in a region is constant, the electric field must be zero everywhere in that region. A) True B) False
A) True
Which of the following statements about ß+ decay are correct? During ß+ decay A) a proton in the nucleus decays to a positron and a neutron B) the atomic number Z of the isotope increases by one unit but the atomic weight A remains unchanged. C) an orbital electron is captured by the nucleus D) a proton is emitted from the nucleus E) a neutron in the nucleus decays to a proton and an electron
A) a proton in the nucleus decays to a positron and a neutron
Materials in which the electrons are bound very loosely to the nuclei and can move about freely within the material are referred to as A) conductors B) superconductors C) polar D) insulators E) semiconductors
A) conductors
Monochromatic light strikes a metal surface and electrons are ejected from the metal. If the intensity of the light is increase, what will happen to the ejection rate and maximum energy of the electrons?
A) greater ejection rate; same maximum energy
Consider the four quantum numbers of an electron in an atom, n, l, m(subl), and m(subs). The energy of an electron in an isolated atom depends on
A) n only
In an electromagnetic wave, the electric and magnetic fields are oriented such that they are A) perpendicular to one another and perpendicular to the direction of wave propagation. B) perpendicular to one another and parallel to the direction of wave propagation. C) parallel to one another and perpendicular to the direction of wave propagation. D) parallel to one another and parallel to the direction of wave propagation.
A) perpendicular to one another and perpendicular to the direction of wave propagation.
A 4.0-cm tall object is placed 60 cm away from a converging lens of focal length 30 cm. What are the nature and location of the image? The image is
A) real, 4.0 cm tall, and 60 cm from the lens on the side opposite the object
A wire has a cross-sectional area of 0.10 mm^2. If there are 4.0 x 10^28 atoms per cubic meter in this wire, and if each atom contributes 2 free electrons, what is the drift velocity of the electrons when the current in the wire is 6.0 A? A) 0.94 m/s B) 0.0047 m/s C) 0.0092 m/s D) 0.019 m/s
B) 0.0047 m/s
An electric dipole is made of two charges of equal magnitudes and opposite signs. The positive charge, q = 1.0 uC, is located at the point (x, y, z) = (0.00 cm, 1.0 cm, 0.00 cm), while the negative charge is located at the point (x, y, z) = (0.00 cm, -1.0 cm, 0.00 cm). How much work will be done by an electric field E = (3.0 x 10^6 N/C)i to bring the dipole to its stable equilibrium position? A) 0.00 J B) 0.060 J C) 0.12 J D) 0.030 J E) 0.020 J
B) 0.060 J
A series LR circuit consists of a 2.0-H inductor with negligible internal resistance, a 100-ohm resistor, an open switch and a 9.0-V ideal power source. After the switch is closed, what is the maximum power delivered by the power supply? A) 0.40 W B) 0.81 W C) 0.090 W D) 81 W E) 8.1 W
B) 0.81 W
Three particles travel through a region of space where the magnetic field is out of the page, as shown in the figure. The electric charge of each of the three particles is, respectively, A) 1 is positive, 2 is neutral, and 3 is negative. B) 1 is negative, 2 is neutral, and 3 is positive. C) 1 is neutral, 2 is positive, and 3 is negative. D) 1 is neutral, 2 is negative, and 3 is positive. E) 1 is positive, 2 is negative, and 3 is positive.
B) 1 is negative, 2 is neutral, and 3 is positive.
An electron is confined in a one-dimensional box (an infinite well). Two adjacent allowed energies of the electron are 1.068 x 10^-18 J. What is the length of the box?
B) 1.9 nm
What is the energy of an incident photon that is just enough to excite a hydrogen atom from its ground state to its n = 4 state?
B) 12.75 eV
A neutral atom has an electron configuration of 1s^2 2s^2 2p^6 3s^2 3p^2. How many protons does it have in its nucleus?
B) 14
The lowest energy level of a certain quantum harmonic oscillator is 5.00 eV. What is the energy of the nest higher level?
B) 15.0 eV
What is the minimum of an electric field that balances the weight of a plastic sphere of mass 6.4 g that has been charged to -3.0 nC A) 4.5x 10^6 N/C B) 2.1 x 10^7 N/C C) 2.4 x 10^6 N/C D) 6.4 x 10^6 N/C
B) 2.1 x 10^7 N/C
Two point charges of +20.0 µC and -8.00 µC are separated by a distance of 20.0 cm. What is the magnitude of electric field due to these charges at ta point midway between them? A) 25.2 x 10^5 N/C directed toward the negative charge B) 25.2 x 10^6 N/C directed toward the negative charge C) 25.2 x 10^4 N/C directed toward the negative charge D) 25.2 x 10^6 N/C directed toward the positive charge E) 25.2 x 10^5 N/C directed toward the positive charge
B) 25.2 x 10^6 N/C directed toward the negative charge
What is the energy density in the magnetic field 25 cm from a long straight wire carrying a current of 12 A? A) 1.2 x 10^-4 J/m^3 B) 3.7 x 10^-5 J/m^3 C) 3.6 x 10^-4 J/m^3 D) 7.3 x 10^-5 J/m^3 E) the density cannot be determined without knowing the volume.
B) 3.7 x 10^-5 J/m^3
An oil layer that is 5.0 cm thick is spread smoothly and evenly over the surface of water on a windless day. What is the angle of refraction in the water for a ray of light that has an angle of incidence of 45 º as it enters the oil from the air above? (The index of refraction for the oil is 1.15, and for water it is 1.33)
B) 32º
The emf and the internal resistance of a battery are as shown in the figure. If a current of 8.3 A is drawn from the battery when a resistor R is connected across the terminals ab of the battery, what is the power dissipated by the resistor R? A) 530 W B) 440 W C) 620 W D) 790 W E) 700 W
B) 440 W
The figure shows a velocity selector that can be used to measure the speed of a charged particle. A beam of particles is directed along the axis of the instrument. A parallel plate capacitor sets up an electric field E, which is oriented perpendicular to a uniform magnetic field B. If the plates are separated by 2.0 mm and the value of the magnetic field is 0.60 T, what voltage between the plates will allow particles of speed 5.0 x 10^5 m/s to pass straight through without deflection? A) 1900 V B) 600 V C) 94 V D) 190 V E) 3800 V
B) 600 V
A conducting sphere of radius 20.0 cm carries an excess charge of +15.0 uC, and no other charges are present. The potential (relative to infinity) due to the sphere at a point 12.0 cm from its center is closest to A) zero B) 674 kV C) 3380 kV D) 9380 kV E) 1130 kV
B) 674 kV
a 1000-turn toroidal solenoid has a central radius of 4.2 cm and is carrying a current of 1.7 A. What is the magnitude of the magnetic field inside the solenoid at the central radius? A) 51 mT B) 8.1 mT C) 81 mT D) zero E) 16 mT
B) 8.1 mT
Light of frequency 6.00 x 10^14 Hz illuminates a soap film (n = 1.33) having air on both sides of it. When viewing the film by reflected light, what is the minimum thickness of the film that will give an interference maximum when the light is incident normally on it?
B) 94.0 nm
A large magnetic flux change through a coil must induce a greater emf in the coil than a small flux change. A) True B) False
B) False
As current flows through a uniform wire, the wire gets hotter because the electrons stop moving and therefore transform their lost kinetic energy into thermal energy in the wire. A) True B) False
B) False
If the electric field is zero everywhere inside a region of space, the potential must be zero in that region. A) True B) False
B) False
If the electric potential at a point in space is zero, then the electric field at that point must also be zero. A) True B) False
B) False
If two electrons in an atom have the same energy, then they must have the same four quantum numbers. A) True B) False C) They cannot both have the same energy
B) False
Two equal positive charges are held in place at a fixed distance. If you put a third positive charge midway between these two charges, its electrical potential energy of the system (relative to infinity) is zero because the electric forces on the third charge due to the two fixed charges just balance each other. A) True B) False
B) False
An object is placed in front of a lens which forms an image of the object
B) If the image is real, then it is also inverted
The decay rate of an isotope is initially R0, but after one half-life has gone by, the rate is R0/2. At the end of the NEXT half-life, what will the decay rate be?
B) R0/4
A conducting sphere contains positive charge distributed uniformly over its surface. Which statements about the potential due to this sphere are true? All potentials are measured relative to infinity. A) The potential at the center of the sphere is zero. B) The potential at the center of the sphere is the same as the potential at the surface. C) The potential at the center is the same as the potential at infinity. D) The potential is lowest, but not zero, at the center of the sphere. E) The potential at the surface is higher than the potential at the center.
B) The potential at the center of the sphere is the same as the potential at the surface.
A radioactive nuclide of atomic number Z emits an electron, then the daughter nuclide emits a gamma ray. What is the atomic number of the resulting nuclide after both processes?
B) Z + 1
If the accuracy in measuring the position of a particle increases, the accuracy in measuring its velocity will
B) decrease
In the figure, two solenoids are approaching each other with speed v as shown. The induced current through the resistor R is A) from b to a B) from a to b C) There is no induced current through the resistor
B) from a to b
A fusion reaction releases energy because the binding energy of the resulting nucleus A) is less than the binding energy of the original nuclei B) is greater than the binding energy of the original nuclei C) is absorbed in the process D) is equal to the binding energy of the original nuclei E) is released in the process
B) is greater than the binding energy of the original nuclei
The neutral deuterium atom, 2-1H, has a mass of 2.014102 u; a neutral hydrogen atom has a mass of 1.007277 u. What is the binding energy of the 2-1H nucleus? (1 u = 931.494 MeV/c^2)
E) 2.2 MeV
Light of wavelength 105 nm falls on a metal surface for which the work function is 5.00 eV. What is the minimum de Broglie wavelength of the photoelectrons emitted from this metal?
C) 0.47 nm
What must be the diameter of a cylindrical 120-m long metal wire if its resistance is to be 6.0 ohm? The resistivity of this metal is 1.68 x 10^-8 ohm-m. A) 0.0325 mm B) 0.065 mm C) 0.65 mm D) 0.325 mm E) 0.65 cm
C) 0.65 mm
Four resistors are connected across an 8-V DC battery as shown in figure. The current through the 9-ohm resistor is closest to A) 0.9 A B) 2 A C) 0.7 A D) 1 A E) 0.5 A
C) 0.7 A
An initially-stationary electric dipole of dipole moment p = (5.00 x 10^-10 Cm)i placed is an electric field E = (2.00 x 10^6 N/C)i + (2.00 x 10^6 N/C)j. What is the magnitude of the maximum torque that the electric field exerts on the dipole? A) 2.80 x 10^-3 Nm B) 2.00 x 10^-3 Nm C) 1.00 x 10^-3 Nm D) 1.40 x 10^-3 Nm E) 0.00 Nm
C) 1.00 x 10^-3 Nm
A parallel-plate capacitor with plate separation of 1.0 cm has square plates, each with an area of 6.0 x 10^-2 m^2. What is the capacitance of this capacitor if a dielectric material with a dielectric constant of 2.4 is placed between the plates, completely filling them? A) 15 x 10^-14 F B) 15 x 10^-12 F C) 1.3 x 10^-10 F D) 64 x 10^-14 F E) 1.3 x 10^-12 F
C) 1.3 x 10^-10 F
A nonrelativistic electron is accelerated from rest through a potential difference. After acceleration the electron has a de Broglie wavelength of 880 nm. What is the potential difference though which this electron was accelerated?
C) 1.9 µV
Fermium-253 has a half-life of 3.00 d. A sample of fermium contains 7.37 x 10^7 nuclei. How long will it take for there to be only 3.36 x 10^6 fermium nuclei in this sample?
C) 13.4 d
a 1.0 uF capacitor has a potential difference of 6.0 V applied across its plates. If the potential difference across its plates is increased to 8.0 V, how much ADDITIONAL energy does the capacitor store? A) 28 uJ B) 4.0 uJ C) 14 uJ D) 2.0 uJ
C) 14 uJ
An electron in a hydrogen atom has orbital quantum number l = 7. How many possible values of the magnetic quantum number m(subl) could it have?
C) 15
What length of a certain metal wire of diameter 0.15 mm is needed for the wire to have a resistance of 15 ohms? The resistivity of this metal is 1.68 x 10^-8 ohm-m A) 16 mm B) 1.6 m C) 16 m D) 160 m E) 16 cm
C) 16 m
A circular coil of radius 5.0 cm and resistance 0.20 ohm is placed in a uniform magnetic field perpendicular to the plane of the coil. The magnitude of the field changes with time according to B = 0.50e^(-20t)T. What is the magnitude of the current induced in the coil at the time t = 2.0 s? A) 9.2 mA B) 1.3 mA C) 2.6 mA D) 7.5 mA E) 4.2 mA
C) 2.6 mA
A 120-Vrms voltage at 60.0 Hz is applied across an inductor, a capacitor, and a resistor in series. If the peak current in this circuit is 0.8484 A, what is the impedance of this circuit? A) 100 ohm B) 20.4 ohm C) 200 ohm D) 120 ohm E) 141 ohm
C) 200 ohm
The speed of light in a material is 0.50c. What is the critical angle of a light ray at the interface between the material and a vacuum?
C) 30º
A 120-Vrms voltage at 1000 Hz is applied to an inductor, a 2.00 µF capacitor and a 100-ohm resistor, all in series. If the rms value of the current in this circuit is 0.680 A, what is the inductance of the inductor? A) 22.8 mH B) 34.2 mH C) 35.8 mH D) 17.9 mH E) 11.4 mH
C) 35.8 mH
What is the critical angle for light traveling from crown glass (n = 1.52) into water (n = 1.33)?
C) 61º
A negative charge is moved from point A to point B along an equipotential surface. Which of the following statements must be true for this case? A) Work is done in moving the negative charge from point A to point B B) Work is required in moving the negative charge from point A to point B C) No work is required to move the negative charge from point A to point B D) The work done on the negative charge depends on the distance between A and B E) The negative charge performs work in moving from point A to point B
C) No work is required to move the negative charge from point A to point B
An RC circuit is connected across an ideal DC voltage source through an open switch. The switch is closed at time t = 0s. Which of the following statements regarding the circuit are correct? A) The capacitor charges to its maximum value in one time constant and the current is zero at that time. B) The potential difference across the resistor and the potential difference across the capacitor are always equal. C) Once the capacitor is essentially fully charged, there is no appreciable current in the circuit. D) The potential difference across the capacitor is always greater than the potential difference across the resistor. E) The potential difference across the resistor is always greater than the potential difference across the capacitor.
C) Once the capacitor is essentially fully charged, there is no appreciable current in the circuit.
Which of the following statements about Gauss's law are correct? A) Gauss's law is valid only for symmetric charge distributions, such as spheres and cylinders. B) If there is no charge inside of a Gaussian surface, the electric field must be zero at points of that surface. C) The Electric flux passing through a Gaussian surface depends only on the amount of charge inside that surface, not on its size and shape. D) Only charge enclosed within a Gaussian surface can produce an electric field at points on that surface. E) If a Gaussian surface is completely inside an electrostatic conductor, the electric field must always be zero at all points on that surface.
C) The Electric flux passing through a Gaussian surface depends only on the amount of charge inside that surface, not on its size and shape. E) If a Gaussian surface is completely inside an electrostatic conductor, the electric field must always be zero at all points on that surface.
How does the mass of the products of a nuclear fusion reaction compare to the mass of the original elements?
C) The mass of the products is less than the mass of the original elements
In a double-slit experiment, if the slit separation is increased, which of the following happens to the interference pattern shown on the screen?
C) The minima get closer together.
A positive charge Q is located at the center of an imaginary Gaussian cube of sides a. The flux of the electric field through the surface of the cube is phi. A second, negative charge -Q is placed next to Q inside the cube. Which of the following statements will be true in this case? A) The magnitude of the net electric field is constant on the entire surface of the cube B) The net flux through the surface is equal to 2phi C) The net flux through the surface of the cube is equal to zero D) The net electric field on the surface of the cube is equal to zero E) The electric field on the surface of the cube is perpendicular to the surface.
C) The net flux through the surface of the cube is equal to zero
In the figure, a straight wire carries a steady current I perpendicular to the plane of the page. A bar is in contact with a pair of circular rails, and rotates about the straight wire. The direction of the induced current through the resistor R is A) from a to b B) from b to a C) There is no induced current through the resistor
C) There is no induced current through the resistor
Which of the following is an accurate statement about light?
C) When light strikes a surface at Brewster's angle, only the reflected light is 100% polarized.
A coil lies flat on a tabletop in a region where the magnetic field vector points straight up. The magnetic field vanishes suddenly. When viewed from above, what is the direction of the induced current in this coil as the field fades? A) clockwise then counter-clockwise B) counter-clockwise then clockwise C) counter-clockwise D) clockwise E) There is no current induced in the coil.
C) counter-clockwise
A negative charge, if free, will tend to move A) from high potential to low potential B) toward infinity C) from low potential to high potential D) away from infinity E) in the direction of the electric field
C) from low potential to high potential
As more resistors are added in parallel to a constant voltage source, the power supplied by the source A) decreases B) does not change C) increases
C) increases
The figure shows three long, parallel, current-carrying wires. The current directions are indicated for currents I1 and I3. The arrow labeled F represents the net magnetic force acting on current I3. The three currents have equal magnitudes. What is the direction of the current I2? A) vertically downward B) out of the picture (in the same direction as I1 and I3) C) into the picture (in the direction opposite to that of I1 and I3) D) vertically upward E) horizontal to the right
C) into the picture (in the direction opposite to that of I1 and I3)
Under electrostatic conditions, the electric field just outside the surface of any charged conductor A) is always zero because the electric field is zero inside conductors B) is always parallel to the surface C) is always perpendicular to the surface of the conductor D) can have nonzero components perpendicular to and parallel to the surface of the conductor is perpendicular to the surface of the conductor only if it is a sphere, a cylinder, or a flat sheet
C) is always perpendicular to the surface of the conductor
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 toward you, and the wire on your left carries current away from you. From your point of view, the magnetic field at the point exactly midway between the two wires A) is zero B) points upward C) points downward D) points toward you E) points away from you
C) points downward
Which one of the following lists is a correct representation of electromagnetic waves from longer wavelength to shorter wavelength? A) radio waves, infrared, microwaves, UV, visible, X-rays, gamma rays B) radio waves, microwaves, visible, X-rays, infrared, UV, gamma rays C) radio waves, microwaves, infrared, visible, UV, X-rays, gamma rays D) radio waves, infrared, X-rays, microwaves, UV, visible, gamma rays E) radio waves, UV, X-rays, microwaves, infrared, visible, gamma rays
C) radio waves, microwaves, infrared, visible, UV, X-rays, gamma rays
An air-filled parallel-plate capacitor is connected to a battery and allowed to charge up. Now a slab of dielectric material is placed between the plates of the capacitor while the capacitor is still connected to the battery. After this is done, we find that A) the voltage across the capacitor had increased B) the energy stored in the capacitor had decreased C) the charge on the capacitor had increased D) the charge on the capacitor had not changed E) None of these choices are true
C) the charge on the capacitor had increased
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?
D) 0.63º
A 400-W computer (including the monitor) is turned on for 8.0 hours per day. If electricity costs 10c per kWh, how much does it cost to run the computer for a 365-day year? A) $15 B) $17 C) $150 D) $120 E) $1200
D) $120
A swimming pool is filled to a depth of 2.0 m. How deep does the pool appear to be from above the water, which has an index of refraction of 1.33?
D) 1.5
A wire of resistivity p must be replaced in a circuit by a wire of the same material but 4 times as long. If, however, the resistance of the new wire is to be the same as the resistance of the original wire, the diameter of the new wire must be A) 4 times the diameter of the original wire B) the same as the diameter of the original wire C) 1/2 the diameter of the original wire D) 2 times the diameter of the original wire E) 1/4 the diameter of the original wire
D) 2 times the diameter of the original wire
Two identical small conducting spheres are separated by 0.60 m. The spheres carry different amounts of charge and each sphere experiences an attractive electric force of 10.8 N. The total charge on the two spheres is -24 uC. The two spheres are now connected by a slender conducting wire, which is then removed. The electric force on each sphere is closest to A) 3.6 N, attractive B) 5.4 N, repulsive C) zero D) 3.6 N, repulsive E) 5.4 N, attractive
D) 3.6 N, repulsive
Find the wavelength of the photon emitted during the transition from the second EXCITED state to the ground state in a harmonic oscillator with a classical frequency of 3.72 x 10^13 Hz.
D) 4.03 µm
The primary coil of a transformer has 100 turns of wire, and its secondary coil has 400 turns. If the ac voltage applied to the primary coil is 120 V, what voltage is present in its secondary coil? A) 30 V B) 400 V C) 70 V D) 480 V E) 100 V
D) 480 V
Three very long, straight, parallel wires each carry currents of 4.00 A, directed out of the page as shown in the figure. The wires pass through the vertices of a right isosceles triangle of side 2.00 cm. What is the magnitude of the magnetic field at point P at the midpoint of the hypotenuse of the triangle? A) 4.42 x 10^-6 T B) 1.77 x 10^-6 T C) 1.26 x 10^-4 T D) 5.66 x 10^-5 T E) 1.77 x 10^-5 T
D) 5.66 x 10^-5 T
The lifetime of an excited nuclear state is 1.0 ns. What is the minimum uncertainty in the energy of this state? (eV)
D) 6.6 x 10^-7 eV
A proton is placed in an electric field of intensity 700 N/C. What are the magnitude and direction of the acceleration of this proton due to this field? A) 6.71 x 10^9 m/s^2 opposite to the electric field B) 6.71 x 10^10 m/s^2 opposite to the electric field C) 67.1 x 10^10 m/s^2 opposite to the electric field D) 6.71 x 10^10 m/s^2 in the direction of the electric field E) 67.1 x 10^10 m/s^2 in the direction of the electric field
D) 6.71 x 10^10 m/s^2 in the direction of the electric field
A single slit forms a diffraction pattern, with the first minimum at an angle of 40.0º from central maximum, using monochromatic light of 490-nm wavelength. What is the width of the slit?
D) 762 nm
Four point charges of equal magnitude and sign are arranged on the corners of the square of side d as shown in Fig 21-5. Which of the arrows represents the net force acting on the charge at the upper right hard corner of the square? A) A B) B C) C D) D E) none of the above
D) D
In a single-slit diffraction experiment, the width of the slit through which light passes is reduced. What happens to the width of the central bright fringe?
D) It becomes wider.
Fig. 21-11 shows 3 electric charges labeled Q1, Q2, Q3 and some electric field lines in the region surrounding the charges. What are the signs of the 3 charges? A) All the charges are negative B) Q1 is positive, Q2 is positive, Q3 is negative C) Q1 is negative, Q2 is positive, Q3 is negative D) Q1 is positive, Q2 is negative, Q3 is positive E) All 3 charges are positive
D) Q1 is positive, Q2 is negative, Q3 is positive
If a nucleus decays by gamma decay to a daughter nucleus, which of the following statements about this decay are correct A) The daughter nucleus has fewer protons than the original nucleus B) The daughter nucleus has fewer neutrons than the original nucleus C) The daughter nucleus has more protons than the original nucleus D) The daughter nucleus has the same number of nucleons as the original nucleus E) The daughter nucleus has more neutrons than the original nucleus
D) The daughter nucleus has the same number of nucleons as the original nucleus
Fig. 23-1 shows equipotentials surrounding a pair of charges QA and QB. The values of the potential half-way between the charges is indicated. Which of the statements below applies to the charges? A) Nothing can be said about the charges B) The two charges have the same sign and equal magnitudes C) The two charges have the same sign but different magnitudes D) The two charges have opposite signs and equal magnitudes E) The two charges have opposite signs and different magnitutdes
D) The two charges have opposite signs and equal magnitudes
A convex lens has focal length f. If an object is located extremely far from the lens (at infinity), the image formed is located what distance from the lens?
D) f
As you walk away from a vertical plane mirror, your image in the mirror
D) is always the same height
When light goes from one material into another material having a HIGHER index of refraction
D) its speed and wavelength decrease, but its frequency stays the same.
A conducting bar slides without friction on two parallel horizontal rails that are 50 cm apart and connected by a wire at one end. The resistance of the bar and the rails is constant and equal to 0.10 ohm. A uniform magnetic field is perpendicular to the plane of the rails. A 0.080-N force parallel to the rails is required to keep the bar moving at a constant speed of 0.50 m/s. What is the magnitude of the magnetic field? A) 0.93 T B) 0.54 T C) 0.10 T D) 0.36 T E) 0.25 T
E) 0.25 T
A pair of charged conducting plates produces a uniform field of 12,000 N/C, directed to the right, between the plates. The separation of the plates is 40 mm. An electron is projected from plate A, directly toward plate B, with an initial velocity of v = 2.0 x 10^7 m/s, as shown in the figure. The velocity of the electron as it strikes plate B is closest to A) 2.1 x 10^7 m/s B) 1.8 x 10^7 m/s C) 1.2 x 10^7 m/s D) 2.4 x 10^7 m/s E) 1.5 x 10^7 m/s
E) 1.5 x 10^7 m/s
When an object 1.15 cm tall is placed 12 cm from a lens, the lens produces an upright image of the object that is 5.75 cm tall. What is the focal length of the lens?
E) 15 cm
An ac source having a maximum voltage output of 30 V is connected in series with a 50-ohm resistor, a 0.60-H inductor, and a 20-µF capacitor. What is the maximum charge on the capacitor when the frequency of the source is adjusted so that the circuit is in resonance? A) 1.0 mC B) 0.00 mC C) 4.2 mC D) 8.4 mC E) 2.1 mC
E) 2.1 mC
A positive charge Q is fixed on a very large horizontal frictionless tabletop. A second positive point charge q is released from rest near the stationary charge and is free to move. Which statement best describes the motion of q after is is released? A) its acceleration is zero just after it is released B) As it moves farther and farther from Q, its acceleration will keep increasing C) Its speed will be greatest just after it is released D) As it moves farther and farther from Q, its speed will decrease E) As it moves farther and farther from Q, its speed will keep increasing
E) As it moves farther and farther from Q, its speed will keep increasing
For an electron moving in a direction opposite to the electric field A) its potential energy decreases and its electric potential decreases. B) both its potential energy and it electric potential remain constant. C) its potential energy increases and its electric potential decreases. D) its potential energy increases and its electric potential increases. E) its potential energy decreases and its electric potential increases.
E) its potential energy decreases and its electric potential increases.
A ray of light goes from one transparent material into another, as shown in the figure. What can you conclude about the indices of refraction of these two materials?
E) n1 > n2
The wave function for a particle must be normalizable because
E) the particle must be somewhere
The figure shows two connected wires that are made of the same material. The current entering the wire on the left is 2.0 A and in that wire the electron drift speed is vd. What is the electron drift speed in the wire on the right side? A) vd/2 B) 2vd C) vd D) 4vd E) vd/4
E) vd/4
Problem 27 Exam 24-26
I1 = 0.194 A I3 = 1/3 A I4 = 1.67 A E3 = 2.33 V P = I^2R
For a uniformly charged sphere with total charge Q and radius R, solve for a) the electrostatic potential outside b) the electric field outside the sphere (you cannot use Gauss's Law) Hint: volume element is dV = r^2sin(theta)d(theta)d(phi)dr phi goes from 0 to 2π theta goes from -π to π
Problem 36 Exam 20-23
Two positive point charges +4.00 µC and +2.00 µC are placed at the opposite corners of a rectangle as shown in the figure. a) What is the potential at point A (relative to infinity) due to these charges? b) What is the potential at point B (relative to infinity) due to these charges?
a) +8.99 x 10^4 V b) 1.12 x 10^5 V
A sinusoidal electromagnetic wave is propagating in vacuum. At a given point P and at a particular time, the electric field is in the +x direction and the magnetic field is in the -y direction. a) What is the direction of propagation of the wave? b) If the intensity of the wave at point P is 0.36 W/m^2, what is the electric field amplitude at that point?
a) -z direction b) 16 V/m
Monochromatic laser light of frequency 5.20 x 10^14 Hz is shown on a pair of thin parallel slits, and the pattern is viewed on a screen 1.20 m away. The fifth bright fringes (not counting the central fringe) occur as +-2.12 cm on either side of the central bright fringe. The entire apparatus is now immersed in a transparent liquid. When the experiment is repeated, the fifth bright fringes now occur at +-1.43 cm from the central bright fringe. a) How far apart are the slits? b) What is the index of refraction of the liquid?
a) 0.163 mm b) 1.48
A 15-turn rectangular loop of wire of width 10 cm and length 20 cm has a current of 2.5 A flowing through it. Two sides of the loop are oriented parallel to a uniform magnetic field of strength 0.037 T, and the other two sides are perpendicular to the magnetic field. a) What is the magnitude of the magnetic moment of the loop? b) What torque does the magnetic field exert on the loop?
a) 0.75 Am^2 b) 0.028 Nm
An uncharged 30.0-µF capacitor is connected in series with a 25.0-Ω resistor, a DC battery, and an open switch. the battery has an internal resistance of 10.0 Ω and the open-circuit voltage across its terminals is 50.0 V. The leads have no appreciable resistance. At time t = 0, the switch is suddenly closed. a) What is the maximum current through the 25.0-Ω resistor and when does it occur (immediately after closing the switch or after the switch has been closed for a long time)? b) What is the maximum charge that the capacitor receives? c) When the current in the circuit is 0.850 A, how much charge is on the plates of the capacitor?
a) 1.43 A, immediately after closing the switch b) 1500 µC c) 608 µC
For the circuit shown in the figure, the switch has been open for a very long time. a) What is the potential drop across the 15.0-mH inductor just after closing the switch? b) What is the potential drop across the 70.0-µF capacitor after the switch has been closed for a very long time?
a) 150.0 V b) 133 V
Consider the circuit shown in the figure. The battery has emf = 25 volts and negligible internal resistance. The inductance is L = 0.08 H and the resistances are R1 = 12 Ω adn R2 = 9.0 Ω. Initially the switch S is open and no currents flow. Then the switch is closed. a) What is the current in the resistor R1 just after the switch is closed? b) After leaving the switch closed for a very long time, it is opened again. Just after it is opened, what is the current in R1?
a) 2.1 A B) 2.8 A
For the circuit shown in the figure, determine the current in a) the 1.0-Ω resistor b) the 3.0-Ω resistor c) the 4.0-Ω resistor
a) 2.8 A b) 1.2 A c) 0.90 A
An object 1.25 cm tall is placed 100 cm in front of a convex lens with a focal length of magnitude 50 cm. A concave lens with a focal length of magnitude 20 cm is placed 90 cm beyond the first lens. a) What is the location of the final image? b) What is the magnification of the final image? c) Is the image real or virtual?
a) 20 cm behind second lens b) m = -2 c) real image
Light strikes a 5.0-cm thick sheet of glass at an angle of incidence in air of 50º. The sheet has parallel faces and the glass has an index of refraction 1.50. a) What is the angle of refraction in the glass? b) After traveling through the glass the light re-emerges into the air. What is the final angle of refraction in air? c) As it leaves the glass, by what distance is the path of the ray displaced from what it was before entering the glass?
a) 31º b) 50º c) 1.9 cm
In the two-slit experiment, monochromatic light of frequency 5.00 x 10^14 Hz passes through a pair of slits separated by 2.20 x 10^-5 m. a) At what angle away from the central bright spot does the third bright fringe past the central bright spot occur? b) At what angle does the second dark fringe occur?
a) 4.69º b) 2.34º
A perfectly black sphere 18.0 cm in diameter is held at a temperature of 215ºC. (sigma = 5.670 a 10^-8 W/m^2, Wien displacement law constant is 2.90 x 10^-3 m*K.) a) Near what wavelength does this sphere radiate most strongly? b) If all the radiated energy were at the wavelength found in part a), how many photons would the sphere emit each second?
a) 5.94 µm b) 9.79 x 10^21 photons
An LRC ac series circuit with R = 15 Ω, L = 15 mH, and C = µF, is attached to a 100-V (rms) ac power supply. The frequency of the power supply is adjusted so that the circuit is in resonance. a) What is the rms current in the circuit? b) What is the power dissipated by the circuit?
a) 6.7 A b) 670 W
Consider the n = 9 shell. a) What is the largest value of the orbital quantum number, l, in this shell? b) How many electrons can be placed in this shell?
a) 8 b) 162
A coaxial cable consists of an inner cylindrical conductor of radius R1 = 0.040m on the axis of an outer hollow cylindrical conductor of inner radius R2 = 0.080m and outer radius R3 = 0.090m. The inner conductor carries current I1 = 4.40 A in one direction, and the outer conductor carries current I2 = 7.70 A in the opposite direction. What is the magnitude of the magnetic field at the following distances from the central axis of the cable? a) At r = 0.060 m (in the gap midway between the two conductors) b) At r = 0.150 m (outside the cable)
a) B = 1.47 x 10^-5 T b) B = 4.40 x 10^-6 T
A circular loop of radius 0.10 m is rotating in a uniform external magnetic field of 0.20 T. Find the magnetic flux through the loop due to the external field when the plane of the loop and the magnetic field vector are a) parallel b) perpendicular c) at an angle of 30º with each other
a) zero b) 6.3 x 10^-3 Tm^2 c) 3.1 x 10^-3 Tm^2
