An electron is confined inside a quantum dot, which for this question can be approximated as a one-dimensional quantum box with rigid walls. The ground state has an energy of 0.042 eV.
(a) In your own words, explain why the energy of the ground state of the system is larger than zero.
(b) Calculate the length of the quantum dot.
(c) What wavelength of photon is needed to cause a transition to the next excited state?
(d) Is the wavelength of 2.958 μm observed in the spectrum of the quantum dot? Explain your answer.
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HI please answer these questions with clean handwriting.
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Lauren has a bow that can shoot arrows at speeds of 0.3c. She is travelling across the Great Sandy Desert to her next archery competition on an ultrafast train that moves at a speed of 0.5c. She has set up to practise on the train with a target that is 150 m away from her in the same direction that the train is travelling.
Greg is standing on a platform as the train travels by.
(a) What is the time between the events “Lauren shoots arrow” and “arrow hits target” for Lauren?
(b) How far is Lauren from the target as measured by Greg?
(c) When Lauren shoots an arrow, what is its speed as measured by Greg?
(d) Do either Greg or Lauren measure the proper time between the events described in (a)? Explain your answer.
(e) How long does it take for the arrow to reach the target as measured by Greg?
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1. A mass of 0.019 kg attached to a spring with spring constant 27.0 N/m is pulled to the right 8.0 cm and released. The mass oscillates with a frequency of 6.0 Hz. If the mass is pulled to the right 16.0 cm before being released, what is the frequency?
a. 6.0 Hz
b. 3.0 Hz
c. 1.5 Hz
d. 12 Hz
e. 24 Hz
2. A window loses power/heat energy through a pane of glass to the cold outside. If the thickness of the glass is doubled and the area of the glass is halved, then the power loss to the cold outside will be?
a. one half of the original power loss
b. twice the original power loss
c. the same as the original power loss
d. four times the original power loss
e. one quarter of the original power loss
3. A skater spins on ice. When she pulls in her arms, she reduces her rotational inertia and her angular speed increases. Compared to her initial rotational kinetic energy, the rotational kinetic energy when she has pulled in her arms must be?
a. smaller
b. the same
c. larger
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how do you linearize this data and what is the slope of the line?:
Distance of sphere's fall: .10m time .14 s
distance of sphere's fall: .50 m time .32s
distance of sphere's fall 1.00m time .46 s
distance of sphere's fall 1.7 m time .59 s
distance of sphere's fall 2.00 m time: .63 s
It's a top opening parabola
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For a conservative force F, all if the following are correct
except
A. there exists an associated potential energy function.
B. the line integral of F between points A and B by way of point C
is independent of point C.
C. the line integral of F around a closed path is zero.
D. the line integral of F with limits A and B is independent of the
order of the limits.
E. the force F must be the net force including the internal
force.
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Explain what would happen if we began Charge-to-Mass Ratio of Electrons experiment with a dot on the CRT (cathode-ray tube) screen instead of a line?
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You are to fire a cannon and are trying to hit a target 300 meters due east of your current position. Your cannon fires projectiles with a mass of 2 kg and with an initial speed of 60 m/s. Gravity is pulling the projectile downward at an acceleration of 9.8 m/s2. There is a wind blowing from the north pushing the projectile southward with a force of 3 N. What is the angle θ up from the ground you must aim the cannon, and what is the angle φ the direction you must turn the cannon to the north? There is a large ridge between the cannon and the target, so your angle of inclination θ must be greater than 45 degrees. Use the acceleration vector given by the wind and gravity, the initial velocity, and the initial position (the origin), to find a position function for the projectile. This will depend on t, θ, and φ. Once you have this function, solve for t, θ, and φ.
,
.
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A 0.300-kg puck, initially at rest on a horizontal, frictionless surface, is struck by a 0.200-kg puck moving initially along the x axis with a speed of 2.00 m/s. After the collision, the 0.200- kg puck has a speed of 1.00 m/s at an angle of θ = 53.0° to the positive x axis. (a) Determine the velocity of the 0.300-kg puck after the collision. (b) Find the fraction of kinetic energy lost in the collision.
and please explain
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Explain the relationship between GAST and UT1? What is the relationship between UT1 and UTC?
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Consider an aluminum annular disk with an outer radius 63.2 mm
and inner radius 7.9 mm. The mass of the disk is 464 grams
(HINT: the parameters of the disk are the same as
in the previous pre-lab).
The disk is allowed to rotate on a frictionless table with the
rotation axis at its center. The disk has a small pulley rigidly
mounted at the top concentrically. The pulley's radius is 12.1 mm,
and the mass of the pulley is negligible. A string is wrapped
around the pulley, and a hanging mass of 19.8 g is tied at the
other end of the string. When the mass falls under gravity, it
causes the aluminum annular disk to rotate. Ignore the string's
mass, and assume that the string's motion is frictionless.
What is the angular speed of the aluminum disk when the mass has
fallen 14.5 cm?
ω = _____ rad/s
How long does it take for the mass to reach this point?
t= _____s
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