PL-1) A spring that hangs vertically is 25 cm long when no weight is attached to its lower end. Steve adds 250 g of mass to the end of the spring, which stretches to a new length of 37 cm. What is the spring constant, k, in N/m?

PL-2) Students performing this experiment to calculate the frequency of oscillation of their mass to be 0.65 s-1 (that is, 0.65 Hz). Predict the time, in seconds, between successive peaks in the position vs. time plot they should expect to obtain when they measure the oscillation.

A mass and holder with a total mass of 350 g is hung at the lower end of a spring with a spring constant k of 53.0 N/m. The mass is pulled down 7.0 cm below the equilibrium point and released, setting the mass-spring system into simple harmonic. [Use these data to answer questions PL-3 through PL-5].
PL-3) What is the frequency of this motion in Hertz?

A mass and holder with a total mass of 350 g is hung at the lower end of a spring with a spring constant k of 53.0 N/m. The mass is pulled down 7.0 cm below the equilibrium point and released, setting the mass-spring system into simple harmonic. [Use these data to answer questions PL-3 through PL-5].
PL-4) What is the total mechanical energy in the spring-mass system, in Joules, at the moment it is released?

A mass and holder with a total mass of 350 g is hung at the lower end of a spring with a spring constant k of 53.0 N/m. The mass is pulled down 7.0 cm below the equilibrium point and released, setting the mass-spring system into simple harmonic. [Use these data to answer questions PL-3 through PL-5].
PL-5) After the mass is released, its position and velocity change as the potential energy of the system is converted into the kinetic energy of the mass. At some point, all of the mechanical energy is in the form of kinetic energy (the mass has its maximum velocity), and the potential energy of the spring-mass is zero. Now, imagine you stopped the mass, then restarted the oscillation by pulling the mass 9.0 cm below the equilibrium point. The maximum velocity the mass obtains will be
Group of answer choices
(A) larger, because more potential energy is stored in the system so more kinetic energy results,
(B) larger, because the velocity of the initial pull adds to the second pull,
(C) smaller, because more potential energy is stored in the system so less kinetic energy results,
(D) smaller, because the mass starts at a lower position, so its peak velocity will be lower,
(E) the same, because energy is conserved.
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DC Electric Circuits: The RC Circuit

-Christopher examines his plot of potential difference versus time and notices that the exponent reads “-2t.” He compares this to Eq. 2 in the lab document to determine the time constant for his experiment. What is the time constant? Express your answer in seconds, s.

-Given the set-up of the circuit described in the procedure, when the double-pole double-throw switch is in the vertical position, the capacitor will
Group of answer choices
a- discharge through the bottom resistor only.
b- remain charged until you flip the switch to the other side.
c- discharge through the top resistor only.
d- discharge through the resistance of the voltmeter.

-Emily finds that the resistance of the voltmeter is 6.00 × 10^6 Ω. When it is connected in parallel with a 10,000 Ω resistor, the equivalent resistance is (answer in units of ohms, Ω)

Christopher and Emily examine an RC circuit with a time constant of 0.35 s. If the initial potential difference was 12 V, what was the potential difference across the capacitor after two time constants had passed, while discharging. Express your answer in volts, V.

After recording many measurements, Emily notices that the precision of the measurement is becoming less because of the setting on the meter. She should
Group of answer choices
a- continue to record values until she has thirty values, or it becomes impossible to distinguish one reading from the next.
b- turn the dial on the meter for added precision.
c- assume she has enough measurements and proceed to the next step.
d- recharge the capacitor and start over on a different setting.

Electromagnetic Waves – Intensity and Polarization
-Sean measures the illumination to be 100 lux when he holds the probe 100 mm from the light source. If he doubles the distance from the source, what is the illumination he predicts will occur there? Express your answer in lux.

-Jannette measures the illumination to be 100 lux when she holds the probe 200 mm from the light source. If she halves the distance from the source, what is the illumination she predicts will occur there?
Group of answer choices
a- 50 lux
b- 400 lux
c- 200 lux
d- 100 lux

• Sean measures the illumination to be 100 lux when he holds the probe 100 mm from the light source. He rotates one of the polarizers so that the angle between the two transmission axes of the two polarizers is 90°. What is the predicted illumination that he should observe at the same location? Express your answer in lux.

True or False: “The only real difference between a green, visible light wave and an x-ray is that one has a shorter wavelength than another.”
Group of answer choices
True
False

Electromagnetic Waves – Interference

• Francine records that the diffraction grating has 5000 slits per cm. What is the distance between each of the slits? Express your answer in cm.
• Olivette is performing a diffraction experiment with a single slit. She measures the width of the central bright region on the screen to be 0.048 m. This is also, therefore, the distance between the first locations of destructive interference. How far is one of the regions of destructive interference from the center of the central bright region?
  Group of answer choices
• 0.096 m
• 0.012 m
• 0.048 m
• 0.024 m

–
Jack thinks it would be cool to point the laser directly onto his open eye. Jack
Group of answer choices

• did not read the warning in this lab document.
• is a masochist.
• has endangered his eyes.
• has made all of the above at least conditionally true.

Olivette measures the distance from the single slit to the screen to be 0.200 m. She calculates that the distance from the first-order location of destructive interference to the center of the central bright fringe, y, is 0.002 m. What is the angle at which this location of destructive interference occurs? Express your answer in degrees.

Francine helped Olivette with her experiment and reminded her that the wavelength of the laser was 650 nm. Recall, Olivette measured the distance from the single slit to the screen to be 0.200 m. She also calculated that the distance from the first-order location of destructive interference to the center of the central bright fringe, y, is 0.002 m. Find the lateral width of the slit, as predicted by these measurements and given information. While you may find the answer in m, express your final answer in mm.

Properties of Sound

Sequoia measures the wavelength of the sound in a Kundt’s tube to be 0.340 m. If the instructor tells her that the frequency driving the sound in the tube is 997 Hz, she will calculate a speed of sound in air of
Group of answer choices
a- 2930 m/s
b- 343 m/s
c- She cannot calculate this with the available data
d- 339 m/s

When Sequoia measured the sound from the tube open at one end and closed at the other, she only observed three, equally-spaced, peaks in the Fourier transform window, and thus recorded three frequencies. What are the values of the harmonic number, n, that correspond to these three peaks?
Group of answer choices
a- n = 1, 2, and 3
b- n = 1, 3, and 5
c- n = 1, 2, and 4
d- n = 0, 1, and 2

When Sequoia measured the sound from the tube open at one end and closed at the other, she only observed three, equally-spaced, peaks in the Fourier transform window, and thus recorded three frequencies (150 Hz, 450 Hz, and 750 Hz). If the length of the tube was 0.55 m, what would be the speed of sound that she would calculate using the fundamental frequency she measured?
Group of answer choices
a- 273 m/s
b- 330 m/s
c- 165 m/s
d- 343 m/s

When Sequoia measured the sound from the tube open at both ends, she only observed three, equally-spaced, peaks in the Fourier transform window, and thus recorded three frequencies (150 Hz, 450 Hz, and 750 Hz). If the length of the tube was 1.10 m, what would be the speed of sound that she would calculate using the fundamental frequency she measured?
Group of answer choices
a- 273 m/s
b- 330 m/s
c- 165 m/s
d- 343 m/s

When Sequoia measured the sound from the tube open at both ends, the Fourier transform plot looked very noisy and had a lot of peaks spread out all over the graph window. She should,
Group of answer choices
a- just pick some of the peaks and move on with the next part of the lab.
b- look over at another group’s data and just copy down the peaks they found for their tube.
c- be sure she is striking the tube before her lab partner hits record, and try again.
d- be sure she is striking the tube after her lab partner hits record, and try again.

Reflection and Refraction of Ligh

A ray of light strikes a flat surface with an angle of incidence of 25°. What is the angle of reflection? Express your answer in degrees.

Selma and Igor are working on measuring the reflected light from the flat face of the mirror. Igor made a mistake and measured the angle of incidence as if it were between the light and the flat face of the mirror, rather than the “normal” line. He should,
Group of answer choices
a- just subtract the angle he measured from 180° because that would basically be the angle of incidence and that’s okay.
b- just subtract the angle he measured from 90° because that would basically be the angle of incidence and that’s okay.
c- start over and repeat the experiment measuring the proper angle.
d- use that angle because it is basically the same thing.

Selma measures an angle of incidence in air of 40° (nair = 1), as a ray strikes the front, flat face of the plastic. If she measures an angle of refraction of 23°. What is the index of refraction of the plastic that she will calculate?

Selma measures an angle of incidence in air of 40° (nair = 1), as a ray strikes the front, flat face of the plastic. If she measures an angle of refraction of 23°. She notices that while some of the light did transmit into the plastic, some of it reflected from the flat surface. What is angle of reflection?

Igor has measured an index of refraction for the plastic of 1.7. He would like to predict the angle of incidence that would result in an angle of refraction of 10°. What is the angle of incidence? Express your answer in degrees and assume nair = 1.

The Lorentz Force and Charge-to-Mass Ratio

Marwin is performing the Lorentz force lab experiment and he has found that the pair-coil has 120 turns, has a radius of 0.15 m, and is carrying a current of 1.5 A. What is the magnitude of the magnetic field in the pair-coil apparatus? Express your answer in milliteslas, mT, and use three significant figures.

Eliza is performing the Lorentz force lab experiment and she is deflecting the beam to the circle on the plate with a radius of 2.0 cm. What is the radius of the circular path of the electron beam? Express your answer in meters, m.

Eliza and Marwin are performing the Lorentz force lab experiment and they found that the pair-coil has 120 turns, has a radius of 0.15 m, and is carrying a current of 1.5 A. The plate voltage was 50.0 V. If the beam is currently deflected to the circle on the plate with a radius of 2.0 cm, what is the charge-to-mass ratio that they calculate?
Group of answer choices
a- 9.11×10^31 C/kg
b- 1.60×10^-19 C/kg
c- 1.16×10^-12 C/kg
d-8.59×10^11 C/kg

During the experiment, Eliza should be sure that the current through the field connections never exceeds what value? Express your answer in amps, A.

Suppose that the electron beam was bent to strike the outer circle on the plate within the electron tube by the magnetic field. If the electrons were slowed down (due to a decreased plate potential difference), how would the radius of the circular motion be affected? Consider Eq. 3 in choosing your response.
Group of answer choices
a- The radius would stay the same because even though the electrons will move more slowly, the magnetic force will be weaker.
b- The radius would decrease.
c- The radius would increase.
d- The electrons wouldn’t be able to enter the tube because the gravitational force would be too strong compared to the electrical force.

The Magnetic Field and Faraday’s Law

Consider the discussion of the Earth’s magnetic field and its north magnetic pole. If we imagine the Earth as a big bar magnet, considering the behavior of the magnetic field lines, the north pole of the magnet would be at
Group of answer choices
a- the Earth’s south magnetic pole.
b- the Earth’s north magnetic pole.
c- the equator.
d- the center of the Earth.

A compass needle is a small bar magnet that is used to determine the direction of the magnetic field in a region of space. If you are near a magnetic material and the north pole of the needle points to the right, the direction of the magnetic field in that region of space is actually
Group of answer choices
a- to the right.
b- to the left.
c- up.
d- down.

Javier and Flora are conducting this lab activity and determine that the red side of their 3D compass probe is actually the north pole of the probe magnet and that the blue side is the south pole of the probe magnet. When they bring the probe near the north pole of the bar magnet, the probe magnet should
Group of answer choices
a- orient itself so that the red side points toward the bar magnet.
b- orient itself so that the blue side points toward the bar magnet.
c- orient itself so that neither side points toward the bar magnet.
d- spin wildly out of control.

An EMF and current can be induced in a loop of wire if the magnetic flux through the loop is changing. Which of the following is NOT a means by which the magnetic flux through a loop would change?
Group of answer choices
a- Increase the magnitude of a magnetic field that has a component perpendicular to the area of the loop.
b- Rotate the loop while it is in a magnet field in such a way that sometimes there is a component of the field perpendicular to the area of the loop.
c- Arrange a magnetic field with a component perpendicular to the area of the loop and wait a really long time.
d- Arrange a magnetic field with a component perpendicular to the area of the loop and increase or decrease the area of the loop.

Javier and Flora observe that when they move the south pole of the bar magnet toward the loop, the reading on the voltmeter is negative, whereas when they moved the north end of the bar magnet toward the loop the reading was positive. While this only measures the EMF generated in the loop, this means that the current that is flowing in the loop in each case must be
Group of answer choices
a- nonexistent because nothing is really happening.
b- in the same direction.
c- zero, because they will cancel each other out.
d- in opposite directions.