CP2 final - cumulative
Magnetic domains are usually randomly oriented. This can be changed by
Bringing a magnet close to the sample
what are the 2 types of reflection
diffuse and specular
chromatic aberration in lenses is due to the
dispersion of light by the lens
a biologist changes the objective lens of a microscope, replacing a 20x with a 10x. to keep the magnification the same, the focal length of the eyepiece must be
halved
A photon of yellow light and a photon of violet light are traveling in vacuum. The photon of yellow light
has a longer wavelength than a photon of violet light and travels with the same speed.
objects that subtend a larger angle in the eye are perceived to be
larger
the screen in a pinhole camera is moved farther away from the pinhole. the image on the screen will be
larger
for a diverging lens, rays that enter the lens directed along lines toward the far focal point emerge from the lens
parallel to the optical axis
what causes the image of an object in water when the observer is in air to appear closer than it is
refraction
what can cause a change in the direction of a light ray
refraction, reflection, scattering
Two loops of wire are parallel to each other and close to each other. They have current passing through them in opposite directions. If the loops are free to move what will happen?
repel each other
what circuit element has a zig zag for its symbol
resistor
light of the same wavelength passes through two diffraction gratings. one grating has 4000 lines/cm and the other has 6000 lines/cm. which grating will spread the light through a larger angle in the first order pattern
the 6000 line grating
which has a larger resistance, a 60W or 100W lightbulb
the 60W
the thin lens equation relates the focal length of a lens or mirror to
the object distance and the image distance
is it possible to see a virtual image
yes because the rays that appear to come from a virtual image can be focused by the eye just like those from an object
You have a choice between two lenses of focal lengths fa and fb, where fb = 2fa, to use as the objective lens in building a compound microscope. If the magnification you obtain using lens a is Ma, what will be the magnification when using lens b?
Mb=Ma/2
What is the property of the copper in the track that leads to the braking force on the toy car?
Good electrical conductor
How many time constants does it take to discharge a capacitor in an RC circuit?
Never fully discharged but 5 is accepted as the time it takes
Which element listed below is ferromagnetic?
Nickel, iron, cobalt
The electromagnetic spectrum consists of
Radio waves, microwaves, infrared light, visible light, ultraviolet light, x-rays and gamma rays
how could you decrease the resistance of a wire
increase the cross sectional area
jamie's far point is 30 cm from her eye and her near point is 10 cm. to correct her vision, jamie needs glasses that create an image of a distant object that is
at her far point
Several capacitors are connected in series with a battery. The charge on the capacitors
is the same for each capacitor
the electric potential inside a charged conductor in electrostatic equilibrium
is zero
Two parallel loops of wire with current moving in the same direction are near each other with an imaginary line connecting the centers of both loops and passing through the loops. What is the force between them?
attractive
how are electric forces between several charged objects combined
by adding individual vectors
what types of mirrors always produce upright images
diverging and plane
if the lens of the eye cannot adjust enough to focus on a distant object, what kind of lens should be added to the optical system
diverging lens
according to the sign conventions, which objects have a negative focal length
diverging lens and diverging mirror
the objective lens of a microscope focuses diverging lens
from the object into a real image
the potential difference between plates of a parallel plate capacitor is
proportional the the charge on the plates
When the north pole of the magnet moves toward the copper a magnetic field is induced in the copper. What direction is the force between the copper and the magnet?
repulsive
in chromatic aberration the focal length for violet light is
shorter than red light
how is refractive power P of a lens related to focal length F
P=1/F
a light ray is
a line in the direction of the flow of the light's energy
the force between an electron and proton is
attractive
how can a single narrow slit produce and interference pattern
each point on the wave front acts as a wavelet source
the electric field of a conductor with +3nC of excess charge
is perpendicular to the surface of the conductor, pointing away from the conductor
a virtual image occurs when
light rays appear to come from a point they did not pass through
total internal reflection can occur when
light travels from higher to lower index of refraction
the resistivity of a good conductor is
lower than insulators
An electron is moving to the left in a magnetic field pointing toward the top of the page. What direction is the resulting force?
out of page
Which plate in a charged capacitor has the higher electric potential?
the + plate
the capacitance of a parallel plate capacitor only depends on
the area of the plates and the distance between the plates
a potential difference can be created by
separating positive and negative charges
colors seen in soap bubbles and oil slicks are due to
the interference of light reflected from the 2 different boundaries
electric field vectors point
toward negative charges and away from positive
The focal length of the lens of a simple digital camera is 5.7 mm, and it is originally focused on a flower 1.5 m away. In what direction must the lens be moved to change the focus of the camera to a tree 100 m away?
towards the CCD sensors
what is the eq. resistance when R1,R2,R3 are connected in parallel
(1/R1+ 1/R2+ 1/R3)^-1
what happens to the electric field in the capacitor as charge stored in it increases
the field increases
the magnification of a microscope is increased when
the focal length of the objective lens is decreased
how are the direction of electric field lines related to equipotential lines
they are perpendicular
what is the relationship between the image distance and the object distance for a plane mirror
they are the same
Which laser pointer (red or violet) outputs the higher energy photons?
violet
Which one of the following sets of characteristics describes the image formed by a plane mirror?
virtual and upright
The parts of the electromagnetic spectrum that can ionize molecules and/or atoms are
Ultraviolet, x-rays and gamma rays
To correct chromatic aberration of a converging lens you should
add diverging lens to the optical instrument
Which equation shows how the frequency, f, and the wavelength, λ, of light are related to the speed of light, c?
c = f*λ
Light with a wavelength of 600 nm travels two different paths to the same point. The lengths of the paths differ by 300 nm what is seen at that point?
destructive interference
the dark bands in the interference pattern in young's double slit experiment are created by
destructive interference
To measure the potential difference at a circuit element a voltmeter must be connected
In parallel with the element to be tested
To measure current in a circuit the ammeter must be connected
In series with the circuit elements
The Earth's magnetic north pole is
Near Earth's south geographic pole
Three identical capacitors are connected in parallel to a potential source (battery). If a charge of Q flows into this combination, how much charge does each capacitor carry?
Q/3
metal spheres 1 and 2 are touching. both are initially neutral. the charged rod is brought near. the spheres are separated. the charge rod is removed. what are the charges on the spheres
Q1 = - Q2 = +
metal spheres 1 and 2 are touching. both are initially neutral. the charged rod is brought near and then removed. the spheres are separated. what are the charges on the spheres
Q1=0 Q2=0
In a circuit model of nerve-impulse propagation, what would happen to the propagation speed if the myalin sheath thickness were larger?
Speed would increase
Changing the angle of a wire loop relative to a magnetic field changes
The magnetic flux
Faraday's law of electromagnetic induction helps determine
The magnitude of induced emfs and currents
when a light wave enters into a medium of different refractive index,
only its speed and wavelength change
a refracting telescope uses
only lenses to create the image
how are car headlights connected
parallel
the electric potential energy of a charge q in terms of the electric potential V =
qV
in a single slit diffraction experiment, how does the angle to the first dark fringe depend on the wavelength of the light used
the angle increases as the wavelength increases
A diffraction grating is essentially many Young's double slits side by side. If the number of slits is changed from 2 to 50 but the distance between each slit remains the same, how does the interference pattern change?
the bright fringes get narrower and brighter
A capacitor is connected to a battery and charged to Q. A dielectric is inserted in the capacitor while it is connected to the battery. Which of the following is true?
the capacitance and charge increases
A capacitor initially has a charge Q on it. As the charge is decreased what happens to the capacitance and the electric field between the plates?
the capacitance is constant and the electric field decreases
The electron-volt is a unit of
energy
the electron volt is a unit of
energy
For relaxed viewing with a microscope, the eyepiece is adjusted to place the final image at
infinity
your camera is focused on a distant mountain and you now want to focus on a nearby flower. you need to
move the lens farther from the camera
Your camera is focused on a distant mountain. Now you want to focus on a nearby flower. You'll need to
move the lens farther from the film
An electron is placed at rest in a uniform electric field. After it is released, what can be said about the motion of the electron and its energy?
moves in direction opposite the electric field, towards decreasing potential energy
when do electric field lines cross
never
what type of lens is used in a pinhole camera
no lens is used
when a beam of light that is traveling in glass strikes an air boundary at the surface of the glass, there is
no phase change in the reflected beam
in ray tracing for a spherical mirror, which ray is reflected back on itself
none
refraction is
the change of direction of light as it moves from one medium to another
The polarization of electromagnetic waves refers to the orientation of
the electric field
electric field lines are closer together when
the electric field is stronger
A cell phone emits EM waves at 1.9 GHz and a microwave oven emits EM waves at 2.4 GHz. Which one emits the shorter wavelength?
the microwave
When light reflects off a mirror, how are the incident angle of the light, θ i, and the reflected angle of the light, θ r, related?
they are equal
capacitors are useful because
they can charge slowly and release energy quickly
When the current passed through 2 identical bulbs connected one after the other, which one was brighter?
they were the same
A parallel plate capacitor has horizontal plates. The top plate has a negative charge, and the bottom plate has a positive charge. What is the direction of the electric field in the capacitor?
up
what direction is the force on an electron due to earths electric field
up
if you tried to use a diverging lens as a magnifier by placing the object at the focal point, what type of image would be produced
upright and smaller than the object
when looking at an object through a magnifier, the focused image you see is
upright and virtual
How do you determine the magnetic force on a negatively charged object moving through a magnetic field?
use the RHR then reverse the direction of force
does the shape of a charged conductor affect the electric field around it?
yes. the field is stronger where the shape is more pointed
If you need to start a fire by using a lens to focus the sun's rays, whose glasses could help?
your far sighted friend
the unit of electric potential is the volt. what is 1V equal to
1 J/C
a spherical mirror is
a section of a sphere
Magnetic field lines point from
From north magnetic poles to south magnetic poles
The equation y m = (m*λ∗L)/d gives the position of the m th bright fringe in a double slit experiment. What is the correction solution for λ in terms of y m, m, L, and d?
λ = (d*y)/(m*L)
How is the potential difference, ΔV, in a capacitor related to the charge, Q, and the capacitance, C?
∆V=Q/C
what is the correct magnification produced by a plane mirror
1
In the model of an ideal wire in a circuit
wires have 0Ω of resistance
what is the electric field inside a conductor with 2nC of net negative charge
0
if a hollow conducting sphere has an excess charge of -10mC, what is the electric field inside the sphere
0 N/C
If the index of refraction of a material is 1.5, this means that light travels
1.5 times as fast in vacuum as it does in the material
wire 2 is twice the length and twice the diameter of wire 1. what is the ratio R2/R1 of their resistances
1/2
the energy stored in a capacitor is equal to
1/2 Q²/c 1/2 Q (∆V) 1/2 C (∆V)²
What is the current in a circuit with a 10 V battery and 1000 ohms of resistance?
10 mA
A circuit consists of 1 battery and 2 identical resistors connected in parallel to the battery. The battery has an emf of 12 V. What is the potential difference across the first resistor?
12 V
A circuit consists of 1 battery and 2 identical resistors connected in series with the battery. The battery has an emf of 12 V. What is the potential difference across both resistors?
12V
the path of the light in raindrops that produces a single rainbow consists of
2 refractions + 1 TIR
What is the potential difference between one plate of a parallel plate capacitor and a point halfway between the plates if the full potential difference between the plates is 5 V?
2.5 V
the typical near point distance for humans is
25cm
the eq. resistance of 2 identical resistors with resistance R which are connected in series is
2R
how many special rays are used in ray tracing to find the image of a lens
3
A circuit consists of a capacitor C and a resistor R connected in series with a battery and an open switch. If a second capacitor of capacitance 2C is connected in parallel with the first one, the time constant of the new RC
3 times as large as before
You are given a copper bar of dimensions 10 cm × 5 cm × 2 cm and asked to attach leads to it in order to make a resistor. If you want to achieve the largestpossible resistance, you should attach the leads to the opposite faces that measure
5 cm x 2cm
15. An object is hung using a metal spring. If now a current is passed through the spring, what will happen to this system?A) The spring will contract, raising the weight.B) The spring will extend, lowering the weight.C) The weight will not move.D) The spring will begin to swing like a pendulum.E) None of these are true.
A
23. An electromagnetic wave is propagating towards the west in free space. At a certain moment the direction of the magnetic field vector associated with this wave points vertically upward. What is the direction of the electric field vector? A) horizontal and pointing south B) vertical and pointing down C) horizontal and pointing north D) vertical and pointing upward E) horizontal and pointing east
A
24. Increasing the brightness of a beam of light without changing its color will increase A) the number of photons per second traveling in the beam. B) the energy of each photon. C) the speed of the photons. D) the frequency of the light. E) the wavelength of the photons.
A
4. Four unequal resistors are connected in a parallel with each other. Which one of the following statements is correct about this combination?A) The equivalent resistance is less than that of the smallest resistor.B) The equivalent resistance is equal to the average of the four resistances.C) The equivalent resistance is midway between the largest and smallest resistance.D) The equivalent resistance is more than the largest resistance.E) None of the other choices is correct.
A
8. A resistor, an uncharged capacitor, a dc voltage source, and an open switch are all connected in series. The switch is closed at time t = 0 s. Which one of the following is a correct statement about this circuit? A) The charge on the capacitor after four time constants is about 98% of the maximum value. B) The charge on the capacitor after one time constant is 50% of its maximum value. C) The charge on the capacitor after one time constant is 1/e of its maximum value. D) The voltage on the capacitor after one time constant is 1/e of the maximum value. E) The voltage on this capacitor after one time constant is 100% of its maximum value.
A
A blue laser beam is incident on a metallic surface, causing electrons to be ejected from the metal. If the frequency of the laser beam is increased while the intensity of the beam is held fixed, A) the rate of ejected electrons will decrease and their maximum kinetic energy will increase. B) the rate of ejected electrons will remain the same but their maximum kinetic energy will increase. C) the rate of ejected electrons will increase and their maximum kinetic energy will increase. D) the rate of ejected electrons will remain the same but their maximum kinetic energy will decrease.
A
Copper wire #1 has a length L and a radius b. Copper wire #2 has a length 2L and a radius 2b. Which statement about the resistance across the ends of the wires is true? A) The resistance of wire #1 is twice as high as that of wire #2. B) The resistance of wire #1 is equal to that of wire #2. C) The resistance of wire #1 is half that of wire #2. D) The resistance of wire #1 is four times higher than that of wire #2.
A
If a proton and an electron have the same speed, which one has the longer de Broglie wavelength? A) the electron B) the proton C) It is the same for both of them.
A
Monochromatic light falls on a metal surface and electrons are ejected. If the intensity of the light is increased, what will happen to the ejection rate and maximum energy of the electrons? A) greater rate; same maximum energy. B) same rate; greater maximum energy. C) greater rate; greater maximum energy. D) same rate; same maximum energy.
A
Observer A sees a pendulum oscillating back and forth in a relativistic rocket and measures its period to be TA. Observer B moves along with the rocket and measures the period of the pendulum to be TB. What is true about these two time measurements? A) TA > TB B) TA = TB C) TA < TB D) TA could be greater or smaller than TB depending on the direction of the motion.
A
The figure shows part of the energy level diagram of a certain atom. The energy spacing between levels 1 and 2 is twice that between 2 and 3. If an electron makes a transition from level 3 to level 2, the radiation of wavelength λ is emitted. What possible radiation wavelengths might be produced by other transitions between the three energy levels? A) both λ/2 and λ/3 B) only λ/2 C) both 2λ and 3λ D) only 2λ
A
To which of the following values of n does the longest wavelength in the Balmer series correspond? A) 3 B) 5 C) 1 D) 7 E) ∞ (very large)
A
9. An uncharged capacitor is connected in series with a resistor, a dc battery, and an open switch. At time t =0 s, the switch is closed. Which of the graphs below best describes the charge Q on the capacitor as a function of time t?
A charge increases with time quadratically
When two or more different capacitors are connected in series across a potential source, which of the following statements must be true? (There could be more than one correct choice.) A) The total voltage across the combination is the algebraic sum of the voltages across the individual capacitors. B) Each capacitor carries the same amount of charge. C) The equivalent capacitance of the combination is less than the capacitance of any of the capacitors. D) The potential difference across each capacitor is the same. E) The capacitor with the largest capacitance has the most charge.
A B C
When two or more different capacitors are connected in parallel across a potential source (battery), which of the following statements must be true? (There could be more than one correct choice.) A) The potential difference across each capacitor is the same. B) Each capacitor carries the same amount of charge. C) The equivalent capacitance of the combination is less than the capacitance of any one of the capacitors. D) The capacitor with the largest capacitance has the largest potential difference across it. E) The capacitor with the largest capacitance has the most charge.
A E
Induced current is current created by
A changing magnetic field
Two current carrying wires parallel to each other exert
A repulsive or attractive force depending on the directions of the currents
Two sources emit beams of light of wavelength 550 nm. The light from source A has an intensity of 10 µW/m2, and the light from source B has an intensity of 20 µW/m2. This is all we know about the two beams. Which of the following statements about these beams are correct? (There could be more than one correct choice.) A) Beam B carries twice as many photons per second as beam A. B) A photon in beam B has twice the energy of a photon in beam A. C) The frequency of the light in beam B is twice as great as the frequency of the light in beam A. D) A photon in beam B has the same energy as a photon in beam A. E) None of the above statements are true.
A,D
Several capacitors are connected in series with a battery. The potential difference across each capacitor
Adds to equal the emf of the battery
Which sequence describes how current is created?
An electric potential creates an electric field which creates the current
How are radio waves created?
An oscillating dipole causes an oscillating electric field which induces an oscillating magnetic field
. Consider ground-state helium having two electrons in orbit. If one of the electrons has quantum numbers (n, ℓl, m1, ms) of 1, 0, 0, -1/2 respectively, the quantum numbers for the other electron will be A) 1, 1, 0, -1/2. B) 1, 0, 0, +1/2. C) 1, 1, 1, +1/2. D) none of the given answers.
B
Current in a wire creates a magnetic field
Around the wire
12. When the switch is closed in the circuit shown in the figure, the wire between the poles of the horseshoe magnet deflects upward. From this you can conclude that the left end of the magnet isA) a north magnetic pole.B) a south magnetic pole.C) There is not enough information given to answer the question.
B
14. 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? A) It is doubled. B) It stays the same. C) It is tripled. D) It is quadrupled. E) It is reduced by a factor of two.
B
18. A coil lies flat on a level tabletop in a region where the magnetic field vector points straight up. The magnetic field suddenly grows stronger. When viewed from above, what is the direction of the induced current in this coil as the field increases? A) counterclockwise B) clockwise C) clockwise initially, then counterclockwise before stopping D) There is no induced current in this coil.
B
19. An outer metal ring surrounds an inner metal ring, as shown in the figure. The current in the outer ring is counterclockwise and decreasing. What is the direction of the induced current in the inner ring? A) clockwise B) counterclockwise C) There is no induced current in the inner ring.
B
20. A bar magnet is oriented above a copper ring, as shown in the figure. If the magnet is pulled upward, what is the direction of the current induced in the ring, as viewed from above? A) There is no current in the ring. B) counterclockwise C) clockwise
B
If the wavelength of a photon in vacuum is the same as the de Broglie wavelength of an electron, which one is traveling faster through space? A) The electron because it has more mass. B) The photon because photons always travel through space faster than electrons. C) They both have the same speed.
B
The energy difference between adjacent orbit radii in a hydrogen atom A) increases with increasing values of n. B) decreases with increasing values of n. C) remains constant for all values of n. D) varies randomly with increasing values of n
B
The orbital angular momentum quantum number ℓ can have any integer value ranging from A) 0 to n. B) 0 to (n-1). C) 1 to n. D) 1 to (n+1). E) -n to n.
B
Two sources emit beams of microwaves. The microwaves from source A have a frequency of 10 GHz, and the ones from source B have a frequency of 20 GHz. This is all we know about the two beams. Which of the following statements about these beams are correct? (There could be more than one correct choice.) A) Beam B carries twice as many photons per second as beam A. B) A photon in beam B has twice the energy of a photon in beam A. C) The intensity of beam B is twice as great as the intensity of beam A. D) A photon in beam B has the same energy as a photon in beam A. E) None of the above statements are true.
B
What magnetic field, B, is needed to create a motional emf for a conductor moving at speed v that is d long.
B = emf/(vd)
How does the magnetic field, B, of a current carrying wire depend on the current, I, and the distance, r, from the wire?
B is proportional to I/r
Two protons are released from rest, with only the electrostatic force acting. Which of the following statements must be true about them as they move apart? (There could be more than one correct choice.) A) Their electric potential energy keeps increasing. B) Their kinetic energy keeps increasing. C) Their electric potential energy keeps decreasing. D) Their kinetic energy keeps decreasing. E) Their acceleration keeps decreasing.
B,C,E
The force needed to pull a wire along conducting rails in a magnetic field is proportional to
B^2
10. Which one of the following statements is correct?A) Earth's geographic north pole is the north pole of Earth's magnetic field.B) Earth's geographic south pole is the south pole of Earth's magnetic field.C) The north pole of a magnet points towards Earth's geographic north pole.D) The north pole of a magnet points towards Earth's geographic south pole.E) None of the above statements is correct.
C
11. 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 A) causes the particle to speed up. B) causes the particle to slow down.C) causes the particle to accelerate. D) is in the same direction as the particle's velocity.E) is opposite the direction of the particle's velocity.
C
13. 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?A) 16F B) 8F C) 4F D) 2F E) F
C
17. A flat coil is in a uniform magnetic field. The magnetic flux through the coil is greatest when the plane of its area is A) parallel to the magnetic field. B) at 45° with the magnetic field. C) perpendicular to the magnetic field.
C
22. In an electromagnetic wave in free space, the electric and magnetic fields are A) parallel to one another and perpendicular to the direction of wave propagation. B) parallel to one another and parallel to the direction of wave propagation. C) perpendicular to one another and perpendicular to the direction of wave propagation.D) perpendicular to one another and parallel to the direction of wave propagation.
C
4. A 30-year-old astronaut goes off on a long-term mission in a spacecraft that travels at speeds close to that of light. The mission lasts exactly 20 years as measured on Earth. Biologically speaking, at the end of the mission, the astronaut's age would be A) more than 50 years. B) exactly 50 years. C) less than 50 years. D) exactly 30 years. E) exactly 25 years.
C
7. Kirchhoff's loop rule is a statement ofA) the law of conservation of momentum.B) the law of conservation of charge.C) the law of conservation of energy.D) the law of conservation of angular momentum.E) Newton's second law.
C
A parallel-plate capacitor consists of a set of two parallel plates of area A separated by a distance d. This capacitor is connected to a battery that maintains a constant potential difference across the plates. A slab of a dielectric material is inserted in the region between the plates and completely fills it. What changes would you observe as the dielectric is inserted? (There could be more than one correct choice.) A) Only the charge on the plates of the capacitor would change. B) Only the capacitance would change. C) Both the charge on the plates of the capacitor and its capacitance would change. D) The potential difference across the plates would increase. E) Nothing would change.
C
A proton and an electron are both accelerated to the same final kinetic energy. If λp is the de Broglie wavelength of the proton and λe is the de Broglie wavelength of the electron, then A) λp > λe. B) λp = λe. C) λp < λe.
C
A really high-speed train moves in a direction parallel to its length with a speed that approaches the speed of light. The length of the train, as measured by a stationary observer on the ground, A) approaches infinity. B) increases due to the motion. C) decreases due to the motion. D) is not affected by the motion.
C
The orbital angular momentum quantum number can take which of the following values for any given value of the principal quantum number, n? A) ℓ = 0, 1, 2, . . . B) ℓ = 0, 1, 2, . . . , n C) ℓ = 0, 1, 2, . . . , (n - 1) D) ℓ = 1, 2, 3, 4, . . . E) ℓ = 1, 2, 3, 4, . . ., (n + 1)
C
What is the atomic number of a neutral atom that has an electron configuration of 1s2 2s2 2p6 3s2 3p2? A) 5 B) 11 C) 14 D) 20
C
Which of the following actions will increase the de Broglie wavelength of a speck of dust? (There could be more than one correct choice.) A) Increase its mass. B) Increase its speed. C) Decrease its mass. D) Decrease its speed. E) Decrease its momentum.
C,D,E
Which of the following are basic postulates of special relativity? (There could be more than one correct choice.) A) Nothing can travel faster than the speed of light. B) No material object can be accelerated to the speed of light. C) The speed of light is the same for all observers. D) The laws of physics are the same in all reference frames. E) The laws of physics are the same in all inertial reference frames.
C,E
the unit of capacitance, F is equal to
C/V
The unit of current is the ampere (amp) which is defined as
C/s
What is the equivalent capacitance for capacitors C1, C2, and C3 when they are connected in parallel?
C1+C2+C3
Cell walls can be modeled as what electric element(s)?
Capacitors and resistors
The auroras near Earth's north and south poles are created by
Charged particle from the sun interacting with Earth's magnetic field
. If n = 5, which one of the following is not an allowed magnetic quantum number m1? A) 0 B) 2 C) 4 D) 5
D
16. Consider two current-carrying circular loops. Both are made from one strand of wire and both carry the same current, but one has twice the radius of the other. If the magnetic field strength at the center of the smaller loop is B, what is the magnetic field strength at the center of the larger loop? A) 8B B) 4B C) 2B D) B/2 E) B/4
D
21. Which one of the following lists gives the correct order of the electromagnetic waves from longer wavelength to shorter wavelength? A) radio waves, infrared, microwaves, ultraviolet, visible, x-rays, gamma rays B) radio waves, ultraviolet, x-rays, microwaves, infrared, visible, gamma rays C) radio waves, microwaves, visible, x-rays, infrared, ultraviolet, gamma rays D) radio waves, microwaves, infrared, visible, ultraviolet, x rays, gamma rays E) radio waves, infrared, x-rays, microwaves, ultraviolet, visible, gamma rays
D
5. You obtain a 100-W light bulb and a 50-W light bulb. Instead of connecting them in the normal way, you devise a circuit that places them in series across normal household voltage. If each one is an incandescent bulb of fixed resistance, which statement about these bulbs is correct?A) Both bulbs glow with the same brightness, but less than their normal brightness.B) Both bulbs glow with the same brightness, but more than their normal brightness.C) The 100-W bulb glows brighter than the 50-W bulb.D) The 50-W bulb glows more brightly than the 100-W bulb.
D
6. You obtain a 100-W light bulb and a 50-W light bulb. Instead of connecting them in the normal way, you devise a circuit that places them in series across normal household voltage. If each one is an incandescent bulb of fixed resistance, which statement about these bulbs is correct?A) Both bulbs glow with the same brightness, but less than their normal brightness. B) Both bulbs glow with the same brightness, but more than their normal brightness. C) The 100-W bulb glows brighter than the 50-W bulb.D) The 50-W bulb glows more brightly than the 100-W bulb.
D
A proton is accelerated from rest through a potential difference V0 and gains a speed v0. If it were accelerated instead through a potential difference of 2V0, what speed would it gain? A) 8v0 B) 4v0 C) 2v0 D) v0^√2
D
An ideal parallel-plate capacitor has a capacitance of C. If the area of the plates is doubled and the distance between the plates is halved, what is the new capacitance? A) C/4 B) C/2 C) 2C D) 4C
D
The length of a certain wire is doubled and at the same time its radius is also doubled. What is the new resistance of this wire? A) It stays the same. B) It is 2 times as large. C) It is 4 times as large. D) It is 1/2 as large. E) It is 1/4 as large.
D
The special theory of relativity predicts that there is an upper limit to the speed of an object. It therefore follows that there is also an upper limit on which of the following properties of the object? (There could be more than one correct choice.) A) The kinetic energy of the object. B) The total energy of the object. C) The linear momentum of the object. D) None of the above.
D
Two uncharged metal spheres, #1 and #2, are mounted on insulating support rods. A third metal sphere, carrying a positive charge, is then placed near #2. Now a copper wire is momentarily connected between #1 and #2 and then removed. Finally, sphere #3 is removed. In this final state A) spheres #1 and #2 are still uncharged. B) sphere #1 carries positive charge and #2 carries negative charge. C) sphere #1 carries negative charge and #2 carries positive charge. D) spheres #1 and #2 both carry positive charge. E) spheres #1 and #2 both carry negative charge.
D
Which of the following changes will increase the capacitance of a parallel-plate capacitor? (There could be more than one correct choice.) A) increase the charge on the plates B) decrease the potential between the plates C) increase the potential between the plates D) introduce a dielectric material between the plates E) decrease the separation between the plates
D, E
In outer space, a positive charge q is released near a positive fixed charge Q, as shown in the figure. As q moves away from Q, what is true about the motion of q? (There may be more than one correct choice.) A) It will move with decreasing speed. B) It will move with constant acceleration. C) It will move with increasing acceleration. D) It will move with decreasing acceleration. E) It will move with increasing speed.
D,E
The exponential behavior of an RC circuit occurs
During charging and discharging of the capacitor
A really high-speed train moves in a direction parallel to its length with a speed that approaches the speed of light. The height of the train, as measured by a stationary observer on the ground, A) approaches infinity. B) approaches zero. C) increases slightly. D) decreases slightly. E) does not change due to the motion.
E
Four unequal resistors are connected in series with each other. Which one of the following statements is correct about this combination?A) The equivalent resistance is equal to that of any one of the resistors.B) The equivalent resistance is equal to average of the four resistances.C) The equivalent resistance is less than that of the smallest resistor.D) The equivalent resistance is less than that of the largest resistor. E) The equivalent resistance is more than the largest resistance.
E
If you were in a spaceship traveling close to the speed of light with respect to Earth, you would notice that A) some of your physical dimensions were smaller than normal. B) your mass was less than normal. C) your mass was greater than normal. D) your pulse rate was greater than normal. E) none of the above effects occur
E
Protons are being accelerated in a particle accelerator. When the energy of the protons is doubled, their de Broglie wavelength will A) increase by a factor of 4. B) increase by a factor of 2. C) decrease by a factor of 2. D) increase by a factor of √2. E) decrease by a factor of √2
E
To which of the following values of n does the shortest wavelength in the Balmer series correspond? A) 3 B) 5 C) 7 D) 1 E) ∞ (very large)
E
Two point charges, Q1 and Q2, are separated by a distance R. If the magnitudes of both charges are halved and their separation is also halved, what happens to the electrical force that each charge exerts on the other one? A) It increases by a factor of 16. B) It increases by a factor of 8. C) It increases by a factor of 2. D) It increases by a factor of 4. E) It remains the same.
E
Which of these equations is correct for the energy of a photon?
E = hf
What is the magnetic force, F, on a wire of length L carrying current I, in a magnetic field B?
F=ILB
what is the force on a charge in an electric field F=
F=QE
Refrigerator magnets
Have multiple poles arranged as long U-magnets
How is the current, I, in a conductor related to the resistance, R, of the conductor and the potential difference across it, ΔV?
I = (ΔV)/R
The induced current, I, due to an induced emf is
I = emf/R
RC circuits can be used for
Intermittent wipers on your car Flashing lights on bicycles Timing in computers
The electrical potential at a resistor in a circuit
Is higher at the end the current enters
The magnetic field inside a current loop
Is in the opposite direction as the field outside the loop
The magnetic field of a solenoid
Is stronger inside the solenoid than outside
electric field due to charge =
K(q/r²)
a charged object moves freely in an electric field. as its electric potential decreases what can be said about it kinetic energy
KE increases
What law describes the directions of eddy currents produced when a conductor moves through a magnetic field?
Lenz
how is the angular magnification of a magnifier related to the focal length of the lens
M=(25cm)/f
Magnets attract
Magnetic materials
MRI's use what property of atoms to produce images?
Magnetic moment of the nucleus
how is the magnification, Mo, of the objective lens in a microscope related to the Fo of the lens
Mo=-L/Fo
The potential difference created by moving a conductor in a magnetic field is called
Motional emf
A proton is placed at rest in a uniform electric field. After it is released, what can be said about the motion of the proton and its energy?
Moves in direction of the electric field, toward increasing kinetic energy
Which of these is a way to create a changing magnetic field?
Moving a circuit relative to a magnet Opening or closing a switch in a circuit Moving a magnet relative to a circuit
The induced current due to a changing magnetic flux produces a magnetic field which
Opposes the change of the flux
The force on a moving charged object in a magnetic field is
Perpendicular to both the magnetic field and the object's velocity
The equivalent resistance of 2 identical resistors, with resistance R, which are connected in parallel is
R/2
what is the eq. resistance when R1 R2 and R3 are connected in series
R1+R2+R3
The time constant for an RC circuit is
RC
What rule is used to determine the force on a current carrying wire due to a magnetic field?
RHR
When current flows in a counterclockwise direction in a current loop the magnetic field created points to the left. What is the field direction when the current is reversed?
Right
What rule is used to determine the direction of the magnetic field created by a current moving in a wire?
Right hand rule
A capacitor is connected to a battery until it has charge Q. It is then disconnected from the battery, maintaining its charge. A dielectric material is introduced between the plates. Which of the following is true?
The capacitance increases and the potential difference decreases.
Kirchhoff's junction law states
The current entering a junction is equal to the current exiting the junction
In order for an electric motor to work
The current must change direction every half cycle
A current loop has a magnetic dipole moment equal to
The current times the area of the loop
Magnetic flux refers to how much magnetic field goes through a loop. The flux depends on the magnetic field and
The effective area of the loop
A photon is
The particle aspect of an electromagnetic wave
A negatively charged rod is brought close to (but does not touch) two neutral metallic spheres that are in contact with each other but insulated from the ground. If the two spheres are then separated, what kind of charge will be on the spheres?
The sphere near the charged rod becomes positive and the other one becomes negative.
The equivalent capacitance of 2 capacitors connected in parallel is
The sum of the capacitances
When capacitors are connected in series
They have the same charge
Cutting a permanent magnet in half creates
Two weaker magnets
What is the electric potential energy of 2 charged objects q1 and q2, when they are separated by a distance r?
U=K(q1 x q2)/r
The electric potential, V, of a point charge is related to the distance, r, from that charge as
V α 1/r
What is true about the work, W, done on a book, and the change in gravitational potential energy, ΔU, of a book when you lift it at a constant speed
W=∆U>0
Which part of the electromagnetic spectrum listed below is the most particle like?
X rays
When a beam of light that is traveling in air is reflected by a glass surface, there is
a 180 phase change in the reflected beam
what is an electric dipole
a neutral object with a separation between positive and negative charges
a parallel plate capacitor creates
a uniform electric field between 2 oppositely charged plates
The author's analogy for a battery in a circuit is
an escalator
single convex spherical mirrors produce images that
are always smaller than the actual object
The electric field and magnetic field of an electromagnetic wave
are perpendicular are in phase are related to the speed of light
Jamie's far point is 30 cm from their eye, and their near point is 10 cm from their eye. To correct their vision, Jamie needs glasses that create an image of distant object that is
at their far point
a converging lens will cause parallel rays of light to
bend to meet at the focal point of the lens
spherical aberration can be minimized by
blocking light rays going through the outer edge of lens
An electromagnetic flowmeter can be used to measure the velocity of
blood and water
when red and blue light pass through a prism which one bends more
blue
When a current flows through an ionic liquid such as salt water, the moving charges are
both positive and negative ions
Consider two aluminum wires of equal length. One wire has twice the diameter of the other. How do the resistivities of these two wires compare?
both wires have the same resistivity
What is the difference between Coulomb's law for forces between charged objects and Newton's law of gravity?
charge forces can be attractive or repulsive while gravity is only attractive
what is the law of conservation of charge
charge is not created or destroyed when transferred
electric fields are created by
charged objects altering the space around them
What type of energy does a battery use to cause charges to move?
chemical energy
Which animal has 4 types of cones in their eyes?
chicken
the wave properties of light can limit telescope resolution by causing
circular diffraction
A conducting loop lies flat on a horizontal tabletop in a region where the magnetic field points straight down. The magnetic field disappears suddenly. When viewed from above, what is the direction of the induced current in this loop as the field disappears?
clockwise
A loop of copper wire is lying flat on a horizontal table. A bar magnet is held above the center of the loop with its south pole downward. The magnet is moved toward the loop. As viewed from above, what is the direction of the current induced in the loop as the magnet approaches the loop?
clockwise
one way to correct chromatic aberration is to
combine a converging lens and a diverging lens
how can charge be moved
contact, polarization, friction
A straight bar magnet is initially 4 cm long, with the north pole on the left and the south pole on the right. If you cut the magnet in half, the left half will
contain a north pole on the left and a south pole on the right.
what type of lens is used to make a magnifying glass
converging
which type of mirror can produce a real image
converging
which two optical objects have a positive focal length based on the sign convention
converging lens and converging mirror
what part of the eye creates the most refraction as light passes through it
cornea
single concave spherical mirrors produce images that
could be smaller than, larger than, or the same size as the actual object, depending on the placement of the object
A changing electric field
creates an induced magnetic field
kirchoffs junction law states that
current into a junction = current leaving it
What is the convention for the direction of charge flow in the context of electric current?
current is the flow of + charge
the electric potential in a charged parallel plate capacitor
decreases from + plate to - plate
properties of current include
deflection of compass needles, warmth, light
when a wave passes through a small opening it spreads to fill the space beyond the opening. this is known as
diffraction
the colors seen on the shiny side of a CD are due to
diffraction due to the holes in the coating
the spreading of different wavelengths of light due to slightly different indices of refraction is known as
dispersion
A moving charged particle is observed to experience no magnetic force. From this we can definitely conclude that
either no magnetic field exists or the particle is moving parallel to the field
What are the charge carriers in a metal?
electrons
a glass rod has been charged to +12nC and touches a metal sphere. what kind of charged particle was transferred and in what direction if the rods charge is now +8nC
electrons moved from sphere to rod
a converging lens creates a real, inverted image. for this to occur, the object must be
farther from the lens than the focal point
accommodation refers to the eyes ability to
focus on both nearby and far objects`
A special microscope allows you to choose the wavelength of light you use. If you have the choice of red or green, which one would you choose to see smaller details?
green
the size of the smallest detail a microscope can resolve is
half the wavelength of the light used
where is the energy stored in a capacitor
in the electric field
the electric potential energy of 2 charged objects with the same sign charge ____ as they are moved closer together
increases
the capacitance of a capacitor can be increased by
inserting an insulator between the plates
what is the orientation of the image on the retina of an eye
inverted
If the magnification of a lens is -0.75, the image is
inverted and smaller than the object
The speed of an electromagnetic wave
is equal to the speed of light
A plastic rod is charged by rubbing with a wool cloth and brought to an initially neutral metallic sphere that is insulated from ground. It is in contact with the sphere for a few seconds, and then is separated from the sphere by a small distance. After the rod is separated, the rod
is repelled by the sphere
the equilibrium position of an electric dipole in an electric field
is with the dipole moment in the same direction as the electric field
in a single slit diffraction experiment, the width of the slit though which light passes is reduced. what happens to the width of the central bright fringe in the resulting diffraction pattern
it becomes wider
if you decrease the distance between 2 charged objects what happens to the force between them
it increases
The length of a certain wire is doubled while its radius is kept constant. What is the new resistance of this wire?
it is 2x as large
If the wavelength of a photon is halved, what happens to its energy?
it is doubled
A beam of light that is coming from the focal point strikes a converging mirror. What happens to the reflected beam?
it is reflected parallel to the principle axis
The index of refraction, n, of a material is a measure of how the speed of light changes. What can be said about the speed of light in a material with n=1.5 compared to a material with n=1.7?
it is slower in the n=1.7
a red razorback uniform appears red because
it reflects red wavelengths
A single-slit diffraction pattern is formed on a distant screen. Assuming the angles involved are small, by what factor will the width of the central bright spot on the screen change if the slit width is halved?
it will double
the potential energy of a charged particle in an electric field is proportional to
its charge
When light travels from glass into air,
its velocity and wavelength change but frequency does not
a battery is connected to a wire and creates a current in the wire. which of the following changes would increase the current
keeping the wire the same length but making it thicker
what is more dangerous, a large electric potential difference or a large charge transfer
large charge transfer
Light has an incident angle of 40° as it leaves a n=1.3 material and enters a n=2.5 material. The angle of refraction is
less than 40
a positive charge released from rest will move in what direction
lower electric potential
The path of a charged object in a magnetic field depends on
mass, velocity, charge
the resistance of a wire to current flow depends on
material of wire, length of wire, cross sectional area of wire
conductors:
materials in which charges move easily
the wave properties of light limit the resolution of
microscopes and telescopes
1 out of 1 points How would you rearrange 2t = (mλ)/n to determine the index of refraction of a thin film
n = (mλ)/(2t)
light goes from material having a refractive index of n1 into a material with refractive index n2. if the refracted light is bent away from the normal, what can you conclude about the indices of refraction
n1>n2
For Snell's Law, n 1*sin(θ 1) = n 2*sin(θ 2) solve for n 2.
n2 = [n1*sin(θ1)]/sin(θ2)
a light bean has speed c in vacuum and speed v in a certain plastic. The index of refraction n of this plastic is
n=c/v
what type of charge can move in a conductor
negative
what is the direction of the electric field in a charged parallel plate capacitor
positive to negative
What is needed in order for current to flow?
potential difference and complete circuit
what does a battery supply
potential difference and energy
kirchoffs loop law says
potential difference around a loop =0
a lightning rod is intended to
prevent lightning strike by ionizing the air around it
a camera records what type of image
real only
if you increase the diameter of a telescope's objective lens and the diameter of the tube with no other changes, the telescope will have the
same magnification with more light collecting power
in order for a color to be visible in thin film interference, the wavelength of the color must
satisfy the constructive interference conditions
why is the sky blue
short wavelengths are scattered more by the atmosphere
in order to get a magnified image of an object, it's distance from a converging lens should be
smaller than the focal length or at the focal length
Computer hard disks
store data using magnetic fields
the tube length of a typical microscope is
the distance from the objective lens to the eyepiece focal point
What happens to the current in the Play-doh when the shape is changed so that it is longer and thinner?
the current decreases
When unequal resistors are connected in series across an ideal battery,
the current flowing in each is the same
in a series circuit with 2 resistors
the current flows through one resistor then the next
As more resistors are added in parallel across a constant voltage source,
the current in the circuit increases and the power supplied by the source increases
In a circuit, how does the current before the resistor compare to the current after the resistor?
the current is the same before and after
in a parallel circuit with 2 resistors
the current splits and flows through both resistors at the same time
in the way that a magnifier is usually used, the object is placed at
the focal point of the lens
you measure a force between 2 charged objects. what happens to the force if the distance between the objects is reduced to 1/2 of what is was
the force increases by a factor of 4
Two tiny beads are 5 cm apart with no other charges or fields present. Bead A carries -20 µC of charge and bead B carries +5 µC. Which one of the following statements is true about the magnitudes of the electric forces on these beads?
the force on A = force on B
how does the fringe spacing change when the distance between the slits, d, is increased
the fringes get closer
If you have a short focal length converging lens what can be said about the power of the lens
the power is large and positive
what happens to the image in a pinhole camera if the screen is moved closer to the pinhole
the image decreases in size
why is the angular magnification of a microscope negative
the image is inverted
if the magnification of an image is -0.4 what can be said about the image
the image is inverted and smaller than the object
a negative value for the magnification of a lens-object combination indicates
the image is inverted relative to the object
Kirchhoff's junction rule is a statement of
the law of conservation of charge
A solid gold cube rests on a wooden table in a region where a uniform external electric field is directed horizontally from left to right. What can be said concerning the charge on the left-hand surface of the cube?
the left hand surface is charged negatively
what is typically moved in a camera in order to focus the image on the detector
the lens
The circuit is constructed so that the blue LED comes on if the current is in one direction and the orange LED comes on if the current is in the other direction. The blue LED comes on when the magnet is quickly placed on the coil. As the magnet is quickly removed from the coil what will happen?
the orange LED comes on
each pair of leads used to make an electrocardiogram meausre
the potential difference between their leads
the energy stored in a capacitor is proportional to
the potential difference squared
The magnetic field of a solenoid does not depend on
the radius of the solenoid
which ray passing through a thin lens does not change direction
the ray going through the center of the lens
A light bulb is in front of a converging lens, creating a well-focused image of the light bulb on the screen on the opposite side of the lens. If the light is moved farther from the lens, how can the screen be adjusted to keep the image in focus?
the screen should be moved closer to the lens
how does the diffraction pattern due to an opaque wire compare to the diffraction pattern due to a slit with the same width
the slit and wire create the same pattern
in circular aperture diffraction, how does the diameter of the hole affect the diffraction pattern
the smaller the hold the wider the central maximum
when light travels from air into water, what happens to the speed of the wave
the speed decreases
Two transparent materials are in contact. The one on the left has a lower index of refraction than the one on the right (n L<n R). Light from the left encounters the boundary between the two materials. Which statement is true about the phases of the wave transmitted through the boundary and the wave reflected from the boundary?
the transmitted wave is unaffected and the reflected wave is inverted
Two long parallel wires are placed side-by-side on a horizontal table. If the wires carry current in opposite directions,
the wires will be repelled by each other
neutral objects have zero net electric charge because
there are equal amounts of positive and negative charge
What direction is the magnetic force on a proton moving in the same direction as a magnetic field?
there is no force
a lens produces a sharply focused inverted image on a screen. what would you see on the screen if the lens were removed
there would be no image
Which one of the following types of electromagnetic wave travels through space the fastest?
they all travel through space at the same speed
converging mirrors will reflect parallel light rays
to the focal point of the mirror
The critical angle for a beam of light passing from water into air is 48.7°. This means that all light rays with an angle of incidence in the water that is greater than 48.7° will be
totally reflected at an angle equal to the incident angle
a converging mirror with a focal length f forms an image of the moon. where is the image
very close to f infront of the mirror
plane mirrors produce
virtual images
another term for the electrical potential difference between 2 points is
voltage
the fundamental resolution of an optical instrument is set by the
wave nature of light
when is the lens of the eye most curved
when looking at near objects
if the speed of light is represented by c, what equation would you use to determine the distance light travels, x, in a time, t
x= ct
