UWL physics 104 final exam (all RQ and HW)
The resolving power of a microscope is the focal length of the objective lens.
False
Part 3: Which of the following options correctly lists the voltage across each resistor? NOTE**** For the circuit shown below, R1=15 Ω, R2=20 Ω, R3=30 Ω, and Vbattery=18 V. (R1 alone and R2 & R3 in parallel)
V1 = 10 V, V2 = 8.0 V, V3 = 8.0 V
How does the index of refraction in water for yellow light compare to that for green light?
Yellow light has a lower index in water compared to green light.
An object with a height of 4.67 cm is placed 48.2 mm to the left of a converging lens with a focal length of 36.0 mm. Find the height and orientation of the image.
13.8 inverted
Two charges, +4.0 micro-C and +3.0 micro-C, are separated by a distance of 35 cm. What is the electric field halfway between the charges?
2.9x10^(5) N/C towards the +3.0 micro-C charge
A 200-ohm resistor is placed in a circuit with four identical batteries connected in series. If the resistor draws 4.0 A, what is the terminal voltage of each battery?
200 Volts
Two point charges, the first with a charge of +4.47 x 10-6 C and the second with a charge of +1.86 x 10-6 C, are separated by 17.4 mm. What is the magnitude of the electrostatic force experienced by charge 2?
247 N **** 2.47 x 10-4 N 103 N 2.74 x 10-8 N
The resistor in an RC circuit has a resistance of 110 Ω and a time constant of 1.9 ms. Calculate the current in the circuit 7.6 ms after the switch is closed. Assume that the capacitor is initially uncharged and that the emf of the battery is 12.0 V.
2mA
A student has a lens with focal length f = 11 cm. Find the maximum magnification produced by this lens.
3.3
A 9.0-V battery is connected across the terminals A and B for the group of resistors shown in the figure. What is the potential difference across R2?
3.6 V
A proton travels at a speed of 3.0x10^(6) m/s through a uniform magnetic field whose magnitude is 8.0x10^(-3) T. What is the magnitude of the magnetic force on the proton if its velocity vector and the magnetic field vector are perpendicular?
3.8x10^(-15) N
Reading glasses with a power of +1.75 diopters make reading a book comfortable for you when you wear them 1.90 cm from your eye. If you hold the book 22.0 cm from your eye, what is your near point distance?
32.9 cm
A proton has an initial speed of 7.9 x 105 m/s. Part 1: What potential difference is required to bring the proton to rest?
3257 Volts
A glass rod rubbed with silk acquires a charge of +7.0x10^(-9) C. How much mass is transferred from the rod?
4.0x10^(-20) kg
An emergency AC generator operates at a rotation frequency of 120 Hz. If the output voltage is zero at t=0, when is it next zero?
4.17x10^(-3) s
What is the magnitude of the magnetic force exerted on a 4.67-m length of wire carrying a current of 2.38 A perpendicular to a magnetic field of 0.385 T?
4.28 Newtons
Part 3: If the moving proton had it's initial speed when it was 1.0 m away from another proton (held at rest), how close would it get to the stationary proton?
4.4 x 10^-13 m
You can increase the strength of a solenoid's magnetic field by inserting an iron core inside the coils of the solenoid.
True
For a fixed voltage, you can increase the power by
decreasing the resistance
The resistance of something
depends on its resistivity and its geometry.
Ohm's law can be applied to AC circuits
if the voltage and current used are rms values.
If the charge on a capacitor is doubled, the energy stored in the capacitor is
quadrupled
The rear window defogger on your car works by Joule heating - converting electrical energy to heat. If the current through those wires doubles, the heating power
quadruples
Compared to solenoid B, solenoid A has ten times the number of turns per meter. The largest magnetic field belongs to
solenoid A
If you are charging an initially uncharged capacitor in an RC circuit, the voltage of the capacitor
starts at zero and increases to the battery voltage.
Visible light is the only really useful type of electromagnetic radiation.
False
The final image formed by two converging lenses is virtual.
false
The speed of an electromagnetic wave
is constant
Electric potential is
scalar quantity
An object placed 20 cm in front of a diverging lens forms an image 4 cm in front of the lens. What is the focal length of the lens?
- 5.0 cm
A convex mirror on the passenger side of a car produces an image of a vehicle that is 11.3 m from the mirror. If the image is located 38.6 cm behind the mirror, what is the radius of curvature of the mirror?
- 80 cm
Images formed by plane mirrors (choose ALL answers that you think are correct)
- have the same heights as their associated objects. - appear to be the same distance behind the mirror as the object is in front of the mirror. - are virtual
We can conserve energy by (choose all answers that are correct)
- using lightbulbs that use less electrical power while producing the same amount of light. - increasing the efficiency of all of our appliances and electrical devices. - following Dad's advice to "turn off the light when you're not in the room". - choosing appliances that minimize power consumption.
The 200-inch-diameter concave mirror of the Hale telescope on Mount Palomar has a focal length of 16.9 m. An astronomer stands 35.0 m in front of this mirror. What is the magnification of her image?
-0.934
The figure shows a circuit with an area of 0.072 m2 containing a R = 3.2-Ω resistor and a C = 120- μF uncharged capacitor. Pointing into the plane of the circuit is a uniform magnetic field of magnitude 0.30 T. In 0.010 s the magnetic field strengthens at a constant rate to become 1.2 T pointing into the plane. What maximum charge (sign and magnitude) accumulates on the upper plate of the capacitor in the diagram?
-780 μC
A solid conducting sphere is surrounded by a thick, spherical conducting shell. A total charge of -Q is initially placed and released at the center of the inner sphere. After equilibrium is reached, how much charge is on the outer surface of the shell?
-Q
A portable CD player operates with a current of 20 mA at a potential difference of 6.2 V. What is the power usage of the player?
0.124 Watts
An aluminum wire is 1.3 m long and has a diameter of 0.05 cm. What is the resistance of the wire?
0.18 Ω
A charge of +3q sits at the origin. A charge of -5q sits on the x-axis at the 1.00 m mark. Given that q=4.11 x 10-9 C, at what location on the x-axis is the electric potential zero?
0.375 m
When an electromagnetic wave travels from one medium to another with a different speed of propagation, the frequency of the wave remains the same. Consider a case where the wave speed decreases from c to 0.45 c. By what factor does the wavelength change?
0.45
Part 2: What is the magnitude of the net ELECTRIC FORCE on the +2.5 μC charge?
0.67 Newtons
A compound microscope has the objective and eyepiece mounted in a tube that is 20.0 cm long. The focal length of the eyepiece is 2.18 cm, and the near-point distance of the person using the microscope is 31.0 cm. If the person can view the image produced by the microscope with a completely relaxed eye, and the magnification is -3500, what is the focal length of the objective?
0.724 mm
A circular coil of wire has a radius of 6.30 cm and has 215 turns of wire that carries 5.90 A of current. What is the magnetic field at the center of the coil?
12.7 mT
Determine the value of the potential 3.50 mm from the positive plate of a pair of parallel plates separated by 12.0 mm and connected to a 18.0-volt battery.
12.8 Volts
A proton has an initial speed of 4.90 x 105 m/s. What potential difference is required to bring the proton to rest?
1250 V
A parallel plate capacitor has plates with an area of 0.019 m2 and a separation of 0.72 mm. The space between the plates is filled with a dielectric whose dielectric constant is 2.4. What is the potential difference between the plates when the charge on the capacitor plates is 5.8 μC?
1.0 x 10^4 V
Magnesium fluoride (n=1.38) is frequently used as a lens (n=1.50) coating to make nonreflecting lenses. What is the difference in the minimum film thickness required for maximum transmission of green light (lambda=520 nm) and yellow light (lambda=580 nm)?
1.09x10^{-8} m
Find the current in resistor R3.
1.25 Amps
If an object is 20 cm in front of a concave mirror that has a focal length of 80 cm, how tall will the image be?
1.3 times as tall as the object.
A 12-V battery is connected to four capacitors in series. The capacitors have the following capacitances: 9 μF, 12 μF, 32 μF, and 42 μF. Find the voltage across the 32 μF capacitor.
1.5 Volts
A small dog sits at a distance of 2.0 m in front of a plane mirror. If the dog jumps away from the mirror with a speed of 0.75 m/s, how fast does the dog recede from its image?
1.5 m/s
What is the equivalent resistance in the following arrangement of resistors? (R1=3.0 ohms, R2=3.0 ohms, R3=4.0 ohms, R4=4.0 ohms)
1.5 ohms
A system of 1728 particles, each of which is either an electron or a proton, has a net charge of +3.552 x 10-17 C. What is the mass of this system?
1.629 x 10-24 kg **** 222.0 kg 1.574 x 10-27 kg 2.886 x 10-24 kg
Laser light with a wavelength λ = 633 nm illuminates a pair of slits at normal incidence. What slit separation will produce first-order maxima at angles of ± 22.0 degrees from the incident direction?
1.69 μm
A cell membrane is 8.7 nm thick and has an electrical resistivity of 1.3 x 107 Ωm. If the potential difference between the inner and outer surfaces of a cell membrane is 63 mV, how much current flows through a circular patch of membrane with radius 1.0 μm?
1.8 x 10-12 A
A horizontal beam of light enters a 45-90-45-degree prism at the center of its long side, as shown in the figure. The emerging ray moves in a direction that is 43 degrees below the horizontal. What is the index of refraction of this prism?
1.82
The average diameter of the eye's pupil during the day is 4.0 mm. What is the minimum angle of separation for two 600 nm sources from which light passes through the pupil of the eye?
1.83x10^(-4) radians
A square loop of wire that encloses an area of 0.20 m^2 is in a uniform magnetic field of 0.10 T. What is the flux through the loop if its plane is at an angle of 62 degrees to the field?
1.8x10^(-2) Wb
A disk drive plugged into a 120-V outlet operates on a voltage of 6.0 V. The transformer that powers the disk drive has 200 turns on its primary coil. Find the number of turns on its secondary coil.
10 turns
You have a semicircular disk of glass with an index of refraction n = 1.43. Find the incident angle θ for which the beam of light in the figure will hit the indicated point on the screen.
11.7 degrees
A single conducting loop of wire has an area of 4.8 x 10-2 m2 and a resistance of 97 Ω. Perpendicular to the plane of the loop is a magnetic filed of strength 1.1 T. At what rate must this field change if the induced current in the loop is to be 0.64 A?
1300 T/sec
A 100-W lightbulb operates on a potential difference of 120 V. Find the resistance of the bulb.
144 Ω
Consider the long, straight current-carrying wires shown in the figure. One wire carries a current I1 = 4.5 A in the positive x-direction; the other wire carries a current I2 = 3.2 A in the negative y-direction. Calculate the net magnetic field at point A.
15 μT, into the page (-z-hat)
A solenoid with 300 turns per centimeter has an iron core with a relative permeability of 100. The solenoid carries a current of 5.0 A. What is the magnetic field at the central axis of the solenoid?
19 T
A 4.0-meter length of straight wire carries a current of 15 A in a uniform magnetic field of 500 micro-T whose field lines make an angle of 45-degrees with the current direction. Find the force on the wire.
2.1x10^(-2) N, perpendicular to the paper
A silver wire is 0.3 m long and has a diameter of 0.05 cm. What is the resistance of the wire?
2.4x10^(-2) ohms
In a flashing neon sign display, the resistance is 5 million ohms, and the time constant is 6.0sec.Suppose you want a time constant of 3.0 sec.
2.5 million ohms
A 6.0-volt battery is connected to a parallel plate capacitor with plate areas of 0.3 meters-squared each and a plate separation of 10 mm. How much energy is stored in the capacitor?
4.8x10^(-9) J
Approximating the eye as a single thin lens 2.35 cm from the retina, find the eye's near-point distance if the smallest focal length the eye can produce is 2.22 cm.
40.1 cm
The distance between lenses of a compound microscope is 20 cm. The focal length of the eyepiece is 20 mm, and the focal length of the objective is 0.5 cm. Find the total magnification of the microscope. Assume the near point distance is 20 cm.
400
A soap film (n = 1.33) is 625 nm thick. White light strikes the film at normal incidence. What visible wavelengths will be constructively reflected if the film sits on a surface of magnesium fluoride (n = 1.38). Visible light has vacuum wavelengths between 400 nm (violet) and 700 nm (red).
416 nm and 554 nm
An AC circuit with a resistance of 10-ohms has an effective current of 3.0 A. Find the peak voltage.
42.4 Volts
An array of solar panels produces 8.65 A of direct current at a potential difference of 148 V. The current flows into an inverter that produces 60-Hz alternating current with Vmax = 84.8 V and Imax = 14.7 A. What is the power efficiency of the converter?
48.7%
Find the frequency of yellow light with a wavelength of 590.0 nm.
5.08 x 10^14 Hz
A slit 0.010 mm wide is illuminated with blue light (lambda=500 nm). How wide is the central maximum formed on a screen 0.5 m from the slit?
5.0x10^{-2} m
How rapidly does the distance between you and your mirror image decrease if you walk toward a mirror at a speed of 3.1 m/s and an angle of 26 degrees to its normal?
5.6 m/s
Blue light (λ = 420 nm) strikes a single slit at normal incidence. What slit width will produce a central maximum that is 2.27 cm wide on a screen 1.55 m from the slit?
57.4 μm
In a physics lab, a student discovers that the magnitude of the magnetic field in a specific location near a long wire is 0.3 micro-T. If the wire carries a current of 10 A, what is the distance from the wire to that location?
6.7 meters
A circular coil with a diameter of 23.4 cm and 210 turns rotates about a vertical axis with an angular speed of 1750 rpm. The only magnetic field in this system is that of the Earth. A the location of the coil, the horizontal component of the magnetic field is 3.65 x 10-5 T, and the vertical component is 2.97 x 10-5 T. Find the maximum emf induced in the coil.
60.3 mV
Part 4: What is the net ELECTRIC FIELD at the center of the triangle?
7.42 x 105 N/C at 39.9 degrees counterclockwise from the +x-axis
Two plane mirrors are placed 75 cm apart with their mirrored surfaces parallel and facing each other. If the mirrors are 10 cm wide, at what angle should a beam of light be incident at one end of one mirror so that it just strikes the far end of the other?
7.6 degrees
Unpolarized light passes through two polarizers whose transmission axes are at an angle of 42.0 degrees with respect to each other. What fraction of the incident intensity is BLOCKED by the polarizers?
72.4%
The armature of an AC generator has 200 turns, which are rectangular loops measuring 5 cm by 10 cm. The generator has a sinusoidal voltage output with an amplitude of 18 V. If the magnetic field of the generator is 300 mT, with what frequency does the armature turn?
9.55 Hz
Standing 1.8 m in front of a small vertical mirror, you see the reflection of your belt buckle, which is 0.63 m below your eyes. What angle do your eyes make with the horizontal when you look at the belt buckle?
9.9 degrees
A 8.45-μC particle with a mass of 6.15 x 10-5 kg moves perpendicular to a 0.493-T magnetic field in a circular path of radius 34.1 m. How much time will it take for the particle to complete one orbit?
92.7 seconds
A certain farsighted person has a near point of 75 cm. Which type of lens should an optometrist prescribe to see objects as close as 20 cm?
A converging lens with power=+3.66 D.
For a given circuit voltage and 10 resistors, which situation provides the largest circuit current?
All resistors in parallel
In the electric circuit diagram below, possible locations of an ammeter and a voltmeter are indicated by circles 1, 2, 3, and 4. Which of the following statements is true?
An ammeter at position 1 will measure the total current provided by the battery
Two charges of +3.5 micro-C are placed at opposite ends of a meterstick. Where on the meterstick could a free proton be in electrostatic equilibrium?
At the 0.5 m mark.
#15) Three charges, q1 = +2.5 μC, q2 = -3.6 μC, and q3 = -5.0 μC, are located at the corners of an equilateral triangle with sides of length 0.5 m centered at the origin. The corner locations are at (-0.250 m, -0.145 m), (+0.250 m, -0.145 m), and (0 m,+0.290 m) respectively. Part 1: Which of the following diagrams correctly shows the ELECTRIC FORCES on the charges?
B
With a battery, direct currents can sometimes flow from the anode to the cathode, but at other times they flow in the opposite direction.
False
The image formed by a plane mirror is formed on the same side of the mirror as the object.
false
Imagine you go for dinner at a friend's house. When leaving, your car will not start. You suspect that your car's battery has died. Your friend offers to "jump start'' your car using their battery. Which of the following arrangements will allow you to start your car? The thick lines represent the jumper cable wires that connect the terminals of the good battery (in your friend's car) to the terminals of the bad battery (in your car)
D, negative to negative and positive to positive
The distance between bright fringes on a screen in a two-slit experiment is independent of wavelength.
False
For a soap bubble, light reflecting from the inner surface of the bubble undergoes a phase-shift of 180-degrees.
False
If the incident angle is less than the the critical angle, then you will have total internal reflection.
False
In reality, magnetic poles can be found as isolated, single objects.
False
Red light is refracted more than blue light.
False
Since they diffract around normal, meter-sized objects, cell phone radio waves must be much shorter than one meter.
False
#12 technically........Part 2: Which of the following options correctly lists the current in each resistor? NOTE**** For the circuit shown below, R1=15 Ω, R2=20 Ω, R3=30 Ω, and Vbattery=18 V. (R1 alone and R2 & R3 in parallel)
I1 = 0.67 A, I2 = 0.4 A, I3 = 0.27 A
Polarizer A is set up so that its polarization direction is vertical. Polarizer B is set up so that its polarization direction is 45 degrees from vertical. Which of the following describes light that has passed through both filters?
It is less intense than the original light and is polarized 45 degrees from vertical.
Part 4: What is the total power dissipated by the circuit? NOTE**** For the circuit shown below, R1=15 Ω, R2=20 Ω, R3=30 Ω, and Vbattery=18 V. (R1 alone and R2 & R3 in parallel)
NOT *** 27 Watts
Part 3: Which of the following is a correct expression for the net ELECTRIC FIELD at the center of the triangle (the origin)? Here, r1, r2, and r3 stand for the distances from the origin to each charge.
NOT*** (cos60 + cos60) x-hat + (sin60- Sin60) y hat
Part 2: If the proton moves in a constant electric field and comes to rest in a distance of 8 μm, what is the magnitude of the electric field involved?
NOT*** 5.15 x 10^-4 N/C
Electric fields are vector quantities. Which of the following descriptions is correct?
Positive charges have electric field vectors that point AWAY FROM the charge.
How would you connect multiple batteries in order to get the biggest possible voltage?
Put all of the batteries in series.
For the circuit shown below, R1=15 Ω, R2=20 Ω, R3=30 Ω, and Vbattery=18 V. (R1 alone and R2 & R3 in parallel) Part 1: Which of the following expressions correctly gives the equivalent resistance of the circuit?
Req = R1 + (R2R3) / R2 + R3
The magnetic field due to an induced current points in a direction opposite to the direction of the field that caused the induced current.
True
Imagine two RC circuits labelled A and B. The resistors in the two circuits are identical, but the capacitor in circuit B has a capacitance twice as large as the capacitor in circuit A (CB=2 CA). If each capacitor is initially fully charged, which capacitor will discharge to 37% of its maximum voltage first?
The capacitor in circuit A because the time constant will be smaller.
An object with charge -Q is placed in an electrically neutral metal cup (without touching the cup). Which of the following best describes the situation?
The electric field in the metal of the cup is zero, the charge in the metal is zero, and the surface charge is -Q. & The electric field in the metal of the cup is zero, the charge in the metal is zero, and the surface charge is +Q
Object A has a net charge of +Q. Object B has a net charge of +2Q. A positive test charge is first brought 1 m from object A. Object A is removed and the same test charge is brought 2 m from object B. Which of the following correctly describes the relative magnitudes of the electric fields experienced by the test charge?
The field due to object A is twice that due to object B
Object A has a net charge of +Q. Object B has a net charge of +2Q. A positive test charge is first brought 1 m from object A. Object A is removed and the same test charge is brought 1 m from object B. Which of the following correctly describes the relative magnitudes of the electric fields experienced by the test charge?
The field due to object B is twice that due to object A.
Two polarizers are set up so that their polarization directions are parallel and vertical. Which of the following describes light that has passed through both filters?
The light is polarized in the vertical direction.
The net force on a current-carrying loop in a uniform magnetic field is zero.
True
Imagine two charges A and B. Charge A is drawn with 8 electric field lines coming from its surface. Charge B is drawn with 16 electric field lines coming from its surface. Which of the following is true?
The magnitude of charge B is twice as large as charge A.
You rub a balloon on your hair and it gains a net negative charge. Which of the following statements is true?
The negative charge gained by the balloon has been lost by your hair, so the net change in the charge of the hair-balloon system is zero.
A positively charged particle enters the magnetic field region of a mass spectrometer and turns to the right. What would happen to an equal-mass particle with a negative charge of equal magnitude?
The negative charged particle would turn to the left..
A ray of light leaves an object and passes through the focal point of a concave spherical mirror. After it reflects from the mirror, which of the following correctly describes its path?
The ray travels parallel to the optical axis.
How are electric potential difference (voltage) and electric potential energy related?
The voltage is the potential energy per unit positive charge.
If you want to create a working battery, which one of the following options MUST occur?
There must be a larger excess of electrons at one electrode than at the other
A step-up transformer increases voltage while at the same time decreasing the current.
True
For a soap bubble, light reflecting from the outer surface of the bubble undergoes a phase shift of 180-degrees.
True
If the amount of charge is fixed, a capacitor can store more energy when the voltage is larger.
True
If the maximum AC current increases to a new value that is twice as large as the original value, the new root-mean-square (rms) current also increases by a factor of 2 over the original value.
True
In a Kirchoff loop, if the loop direction and current direction coincide for a resistor, the voltage is considered to be negative.
True
In order to see a rainbow, the sun needs to be at your back.
True
Negative charges, when allowed to move, go towards regions where the electric potential is high.
True
Rayleigh scattering predicts that the scattering of light is greater for light with short wavelengths.
True
Refraction is due to light propagating at different speeds in different media.
True
The only way for an object to have an electric charge is to have an excess of electrons.
false
In a laboratory, two wires lay next to each other on a bench. Wire A is twice as long as wire B. An experiment causes the two wires to have the same current flowing through them. The wires both exist in the magnetic field of the Earth. Which of the following correctly describes the magnetic force magnitudes experienced by the wires?
Wire A feels twice the force of wire B
According to Ohm's law, a graph of voltage (y-axis) versus resistance (x-axis) would look like
a straight line with slope equal to the current value.
During any complete cycle in which the initial EMF is zero, the EMF of an AC generator becomes zero again at
a time equal to one-half of the total period
An electric charge on the z axis oscillates sinusoidally about the origin. A distant observer is located at a point on the +x axis. At the observer's location, what are the directions of a) the electric field oscillation, b) the magnetic field oscillation, and c) the electromagnetic wave propagation?
a) z-direction, b) y-direction, c) +x-direction
Electromagnetic radiation is caused by
accelerating electric charges
When resistors are connected in parallel, the currents through each resistor
are different with the largest current flowing through the smallest resistor.
Destructive interference occurs when
at least two light waves cancel each other at some location.
In a closed circuit, the movement of electrons is best described as
basically random movement with a slow drift in the direction opposing the current.
An electrically neutral object (like a balloon)
can be subjected to electric forces due to polarization.
An object placed in front of a concave spherical mirror
can form different kinds of images depending on its distance from the mirror.
In order to measure the voltage drop due to a resistor in a circuit, a voltmeter should be
connected in parallel, or "across", the resistor.
Kirchoff's junction theorem is a restatement of which of the following physical laws?
conservation of charge
To correct far-sightedness, a converging lens is used to
create a virtual image at the near point.
Three resistors with values of 7.5 ohms, 9.0 ohms, and 20 ohms are connected in series in a circuit with a 12-volt battery. What is the current in each resistor?
current in resistor 1=0.33 A, current in resistor 2=0.33 A, current in resistor 3=0.33 A.
Electric field lines are drawn parallel to equipotentials.
false
An object with a charge of +6.3 μC and a mass of 0.073 kg experiences an upward electric force, due to a uniform electric field, equal in magnitude to its weight. If the electric charge on the object is reduced by a factor of one-third while its mass remains the same, find the direction and magnitude of its acceleration.
down at 6.5 m/s2
The velocity selector in a mass spectrometer utilizes
electric and magnetic fields.
Part 4: Assuming the moving proton had stopped, which of the following statements is correct?
electric potential from stationary proton is either + or -
By convention, magnetic field lines
exit from N poles and enter at S poles.
ALL rays that are parallel to the optical axis converge at the focal point for a concave spherical mirror.
false
An ideal ammeter has a voltage drop across it.
false
An object placed in front of a convex spherical mirror
forms a virtual image that is always smaller than the object.
A converging lens
has a positive focal length.
An ideal voltmeter
has infinite resistance
As the current increases, the electric power provided by a battery
increases
Relative to the vacuum value, a dielectric always
increases the capacitance.
In a compound microscope, the image formed by the objective lens
is usually very near the focal point of the eyepiece lens.
A double convex lens
makes parallel light rays converge at the focal point.
For a telescope, the fact that light enters the objective lens parallel to the optical axis
means that the objective image is formed at the focal point of the objective lens.
Capacitors connected in series... (Choose ALL answers that are correct)
must have the same charges. & act like one capacitor with an inverse capacitance equal to the sum of the inverses of the individual capacitances.
If the potential increases most rapidly in the positive y-direction, the electric field points in the
negative y-direction.
The focal length of a spherical mirror is equal to
one-half the radius of curvature.
Total internal reflection can occur
only when light travels into a medium with a lower index of refraction.
The magnetic force on a current-carrying wire is greatest when the current is
perpendicular to the magnetic field direction.
The image that is formed by a diverging lens of an object that is outside the focal point has a magnification that is
positive and less than 1
By convention, the direction of an electric field at any point in space is determined by the direction of the electric force on a
positive charge.
In AC circuits, the voltage and current
reach maximum and minium values at the same points in time.
The electric and magnetic fields that make up a light wave
reach maximum values at the same time but oscillate in perpendicular directions.
Light rays are
representations of light that are perpendicular to wavefronts and point in the direction that the light wave propagates.
In a motor, back EMF increases as
the armature loop increases its angular speed.
Imagine an RC circuit that contains a fully charged capacitor. If the capacitor is discharged,
the capacitor voltage and circuit current are largest at the start of the discharge process.
Capacitance increases as
the charge increases and/or the voltage decreases.
Two identical waves destructively interfere when
the crests of one wave occur at the same location as the troughs of the other.
When charging a capacitor in an RC circuit, you expect
the current to decrease with time
In a parallel plate situation, the voltage is 60 V. If the electric potential value at the negative plate is 60 V, then
the electric potential value at the positive plate is 120 V.
The resistance in a conductor like copper increases with length because
the electrons have more opportunity to bounce off of atoms and not participate in the overall flow.
Two lenses that are 42 cm apart are used to form an image. Lens 1 is diverging and has focal length f1 = -8.0 cm; lens 2 is converging and has focal length f2 = 20 cm. The object is placed 13 cm to the left of lens 1. Draw a ray diagram for this situation and use your results to choose the correct description of the image.
the image is real and inverted
If a light ray leaves water and enters air,
the light's speed increases and the angle the ray makes with the normal in air is larger than the angle the ray makes with the normal in water.
A charged particle moving in a direction perpendicular to a uniform magnetic field traces out a circular path because,
the magnetic force provides a centripetal acceleration.
The torque on a current-carrying loop is maximum when
the magnetic moment is perpendicular to the magnetic field direction.
If the distance between two equal positive charges doubles,
the magnitude of the electric force decreases by a factor of 4.
In a Kirchoff loop, the voltage of a battery is treated as positive if the loop is traversed from
the negative to positive terminal
Look at Fig. 19.10(b). If the charge q3 moved closer to charge q1 along the dashed line.....
the net force vector would gain an upward vertical component and its horizontal component would increase.
Imagine you are boating on a lake during a warm summer day. Your polarized sunglasses dramatically cut down the glare from the lake's surface because
the reflected light is significantly polarized in the horizonal direction and your sunglasses have vertical polarizer film.
An equipotential surface is
the set of locations where the electric potential is constant
In the two-slit experiment, a bright interference fringe is produced on a screen when
the two light waves travel distances that are different by any whole (integer) number of wavelengths.
For resistors in parallel,
the voltages across each resistor are equal.
A light wave travels in a medium with an index of refraction n1. It reflects from the surface of a medium with an index of refraction of n2. If n2 > n1, then
the wave undergoes a 180-degree phase change.
Two parallel plates are a distance d apart with a constant electric field E between them. An electron with charge q is released from a point near the negative plate and is made to travel at constant velocity. Which of the following is correct?
the work done by the electric field as the charge moves is +qEd.
If a loop of wire is stretched in a direction perpendicular to the direction of a constant, uniform magnetic field,
then an induced current will run through the loop because the loop encloses a varying number of magnetic field lines.
Two objects with opposite charges are fixed in place (they cannot move). If the charge on the negative object doubles and the positive object's charge remains the same,
then the force on both charges increases by a factor of 2.
If white light is entering a slab of glass with an incident angle of zero relative to the normal,
there will be no dispersion because all wavelengths have zero refraction angles.
If a current flows to the right in a wire that is in a magnetic field that points into your computer screen, the direction of the force on the wire is
towards the top of the screen
The angle of incidence equals the angle of reflection.
true
The angular magnification relates the angular size of an object at some location to the angular size of the image formed by a lens at the same location.
true
The image produced by a diverging lens is always
virtual and reduced
The magnetic flux through a loop of wire is maximum
when the magnetic field direction is perpendicular to the plane of the loop.
Two point charges lie on the x axis. A charge of -2.3 x 10-6 C is at x=-5 cm, and a charge of +9.2 x 10-6 C is at x=12 cm. At what position x would a third positive charge be in equilibrium?
x=-22 cm
A charged object is brought near a neutral electroscope. If the leaves separate,
you know that the object has a net electric charge