An electron is in the ground state of an infinite square well. The energy of the ground state is E1 = 0.46 eV. Use hc=1240 nm eV.
(a) What wavelength of electromagnetic radiation would be needed to excite the electron to the n = 2 state?
(b) What is the width of the square well?
For an electron is in the ground state of an infinite square well, the wavelength of electromagnetic radiation and the width of the square well is mathematically given as
\lambda=67.96nma=0.7nmWhat wavelength of electromagnetic radiation would be needed to excite the electron to the n = 2 state?Generally, the equation for the wavelength is mathematically given as
[tex]\lambda=\frac{hc}{24e}[/tex]
Therefore
\lambda=1240/12.24ev
\lambda=67.96nm
In conclusion, the width of the square well
[tex]a^2=\frac{\pi^2*h^2}{2me}[/tex]
Therefore
[tex]a^2=\frac{9.85*1.10*10^-68}{18.2*10^31*1,21*10^{19}}[/tex]
a^2=0.492*10^18
a=0.7nm
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Answer:
λ=898.5nm
Explanation:
a)
ΔE=hc/λ
ΔE=[tex]E_{2} -E_{1}\\[/tex]
[tex]E_{2} =E_{1} *(n^{2} )[/tex]
Where n equals the new energy level (in this case 2)
so ΔE=(0.46)*4-0.46 = 1.38eV
λ=hc/ΔE
λ=1240nm eV/1.38eV
λ=898.5nm
What is the smallest particle in the Universe?
Answer:
Quarks
Quarks are among the smallest particles in the universe, and they carry only fractional electric charges. Scientists have a good idea of how quarks make up hadrons, but the properties of individual quarks have been difficult to tease out because they can't be observed outside of their respective hadrons.
Answer:
Quarks
Quarks are among the smallest particles in the universe, and they carry only fractional electric charges. Scientists have a good idea of how quarks make up hadrons, but the properties of individual quarks have been difficult to tease out because they can't be observed outside of their respective hadrons.
PLSSSS HELPPPP ASAPPP
A fluorescent light bulb produces just as much light in the same electrical circuit as an incandescent bulb , but requires much less energy to produce it. Which of the following is the most logical explanation for this?
A. The incandescent bulb produces more forms of energy than just light, like heat.
B. The fluorescent light bulb produces more light than any other bulb.
C. The incandescent bulb has to be connected to another circuit.
D. The fluorescent light bulb generates more current than any other type.
Answer:
The most logical explanation is A.
Explanation:
because we are explaining why the incandescent bulb uses less energy we can eliminate answers B and D then, because we are talking about energy efficiency which has nothing to do with connecting to another circuit we can go with, A because Ultraviolet light generated by fluorescent light bulbs is nothing compared to the heat of an incandescent light bulb because it was engineered to be so.
4. An object has a mass in air of 0.0832 kg, apparent mass in water of 0.0673 kg, and apparent mass in another liquid of 0.0718 kg. What is the specific gravity of the other liquid
Question
4. An object has a mass in air of 0.0832 kg, apparent mass in water of 0.0673 kg, and apparent mass in another liquid of 0.0718 kg. What is the specific gravity of the other liquid
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Answer:
Explanation:4. An object has a mass in air of 0.0832 kg, apparent mass in water of 0.0673 kg, and apparent mass in another liquid of 0.0718 kg. What is the specific gravity of the other liquid
Explain, in terms of moments of forces, how the valve works.
The moment of forces in a valve equals force multiplied by the perpendicular distance to the pivot.
What is a Force?This can be defined as an action which changes the motion of an object. A valve is fixed to a pivot and opens and closes thereby controlling flow of fluid.
The moment of forces in a valve is the force multiplied by the perpendicular distance to the pivot.
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Why is cellular reproduction important for homeostasis?
It helps cells make oxygen.
It helps cells make glucose.
It removes waste from cells.
It splits a cell into new cell
Answer:
(It was a remove waste from cells)
Explanation:
the cell produces carbon dioxide and water, which are released as waste.
A swimming pool is an example of an open system. Ther pool loses 10.500 J of its thermal energy to the surrounding air at night, and the surrounding air adds 2,500 J of thermal energy to the morning. According to the law of conservation of energy, what is the change in energy
Answer:
2 and a half cows
Explanation:
There are 14 cows and the farmer consumes 10.
His child then slaughters and consumes one and a half cows.
The farmers wife then takes one to the market.
At todays prices, a singular cow is around £1,577, so to answer your question, the family made £1,577 from the one cow the wife sold.
2
Starting from rest, a child zooms down a frictionless slide from an initial height of 3.00 m. What is her speed at
the bottom of the slide? Assume she has a mass of 25.0 kg
Answer:
About 7.67 m/s.
Explanation:
Mechanical energy is always conserved. Hence:
[tex]\displaystyle \begin{aligned} E_i & = E_f \\ \\ U_i + K_i &= U_f + K_f\end{aligned}[/tex]
Where U is potential energy and K is kinetic energy.
Let the bottom of the slide be where potential energy equals zero. As a result, the final potential energy is zero. Additionally, because the child starts from rest, the initial kinetic energy is zero. Thus:
[tex]\displaystyle U_i = K_f[/tex]
Substitute and solve for final velocity:
[tex]\displaystyle \begin{aligned} mgh_i &= \frac{1}{2}mv_f^2 \\ \\ 2gh_i &= v^2_f \\ \\ v_f &= \sqrt{2gh_i} \\ \\ & =\sqrt{2(9.8\text{ m/s$^2$})(3.00\text{ m})} \\ \\ & \approx 7.67\text{ m/s} \end{aligned}[/tex]
In conclusion, the child's speed at the bottom of the slide is about 7.67 m/s.
What is the door's moment of inertia for rotation about a vertical axis inside the door, 14 cm from one edge
The door's moment of inertia for rotation about a vertical axis inside the door, 14 cm from one edge is 4.205 kgm².
Momnet of inertia about a vertical axis inside the door
The door's moment of inertia for rotation about a vertical axis inside the door, 14 cm from one edge is calculated as follows;
[tex]I = I_{cm} + Md^2[/tex]
where;
I, cm is the moment of inertia about central axisd is the distance from the edgeM is mass of the door[tex]d = \frac{L}{2} - 0.14\\\\d = \frac{0.91}{2} - 0.14\\\\d = 0.315 \ m[/tex]
Moment of inertia[tex]I = \frac{1}{12} ML^2 + Md^2\\\\I = \frac{1}{12} (25)(0.91)^2 \ + \ (25)(0.315)^2\\\\I = 1.725 \ + \ 2.48\\\\I = 4.205 \ kgm^2[/tex]
Thus, the door's moment of inertia for rotation about a vertical axis inside the door, 14 cm from one edge is 4.205 kgm².
The complete question is below;
A 25kg solid door is 220 cm tall, 91 cm wide. What is the door's moment of inertia for rotation about a vertical axis inside the degr, 14 cm from one edge.
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2.3c. What is the frequency of a wave with a length of 12 m that travels at a speed of 36 m/s?
the frequency of the wave is 3
36/12= 3
To reduce auto emissions in the United States, modifications to automobile engines have been required since the 1960s.
a) true
b) false
Answer:
True
Explanation:
A cyclist bikes with an average velocity of 20 m/s for 5 seconds.
What is the magnitude of the cyclist's displacement?
Your answer should have one significant figure.
Explanation:
v = s/t
20 = s/5
100 = s
s = 100 = 1 × 10².
When a cyclist bikes with an average velocity of 20 m/s for 5 seconds, the magnitude of the cyclist displacement would be 1×10² meters.
What is Velocity?
The total displacement covered by any object per unit of time is known as velocity. It depends on the magnitude as well as the direction of the moving object. The unit of velocity is meter/second. It can also be represented by the infinitesimal rate of change of displacement with respect to time. The generally considered unit for velocity is a meter per second.
The mathematical expression for velocity is given by the formula
velocity= total displacement/Total time
The area under the velocity-time graph represents the total displacement covered by the object while the slope of the velocity time graph represents the acceleration of the object.
For the given problem when a cyclist bikes with an average velocity of 20 m/s for 5 seconds,
Displacement =velocity×time
=20×5
=1×10²
The magnitude of the cyclist's displacement is 1×10²
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What is an open circuit?
O A. A circuit that has a gap in the wire
OB. A circuit that uses very little wire
O C. A circuit that conducts an electric current
D. A circuit that has little or no resistance
Answer: A
Explanation:
An open circuit is a circuit that has no current flowing through it. The reason no current can flow through is due to a significant disconnect between two points in the circuit. For example, a large portion of the wire is cut out.
I haven't done any circuit analysis yet, but current can still flow through a circuit even if there is a cut. But that cut has to be extremely small.
Do turtles actually swim or are they ust going with the current?
A.Going with the current
B.Actually swimming
Answer:
Going with the current. You every watch Finding Nemo and the turtle guy says " Going with the waves bro"
Explanation:
Answer:
Young sea turtles make a concerted effort to swim in particular directions, instead of drifting with ocean currents.
A. Going with the current.
A car radio draws 0.28 A of current in the auto's 12-V electrical system. What is the effective resistance of the radio
The effective resistance of the car radio drawing in the given amount of current is 42.86Ω.
Ohm's lawOhm's law states that "the voltage between two points is directly proportional to the current flowing through the resistance.
It is expressed as;
V = IR
Where V is voltage, I is current and R is resistance.
Given the data in the question;
Current drawn by the car radio I = 0.28AVoltage V = 12VEffective resistance of the radio R = ?To determine the effective resistance of the car radio, we substitute our given values into the expression above.
V = IR
12V = 0.28A × R
R = 12V ÷ 0.28A
R = 42.86Ω
Therefore, the effective resistance of the car radio drawing in the given amount of current is 42.86Ω.
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please solve the given question
I know the answer but I need explanation also
PLEASE help
R² = F1² + F2² + 2 F1.F2 cos α ⇒cosinus
F1 and F2 perpendicular, α = 90°, cos 90° = 0
[tex]\tt R=\sqrt{3^3+4^2}=5[/tex]
If you place 1 C of positive charge on Earth and 1 C of negative charge on the moon, 384,500 km away, how much force would the positive charge on Earth experience?
Answer:
6.1 x 10^-8 newtons
Explanation:
F = 8.98 *109 *1*1/3845000002
What is the average velocity if the initial velocity of an object is 10 and the a final velocity is 28
Answer:
19
Explanation:
Avg. Vel = (28 + 10)/2
= 19
BTW, don't forget your units!
When a potential difference of 2 volt is applied across the ends of a wire of 5 metre length a current of 1 ampere flows through it,calculate :-
(i) the resistance per unit length of the wire
(ii) the resistance of 2 metre length of the wire
(iii) the resistance across the ends of the wire if it is doubled on itself
[tex]\huge\underline{\red{A}\green{n}\blue{s}\purple{w}\pink{e}\orange{r} ⟿}[/tex]
(i) 0.4 Ω m^-1
(ii) 0.8 Ω
(iii) 0.5 Ω
Explanation:
(i) Given, V = 2 volt, I = 1 AResistance of 5 m length of wire :-
[tex] = > R = \frac{V}{I} = \frac{2}{1} = 2 \: Ω [/tex]
Resistance per unit length of the wire :-
[tex] = > \frac{R}{l} = \frac{2}{5} = 0.4 \: Ω \: {m}^{ - 1} [/tex]
(ii) Resistance of 2m length of the wire~
[tex] = \: 0.4 \: Ω \: {m}^{ - 1} \times 2 \: m = 0.8 \: Ω [/tex]
(iii) When the wire is doubled on itself, its area of cross section becomes twice and the length becomes half. Let a be the initial cross section and ρ be the specific resistance of the material of wire. Then,
[tex]from \ relation \: \: ➪ \: R = ρ \times \frac{1}{a}. \\ \\ we \: have, \\ \\ initial \: resistance \:➪ \: 2 = ρ\times \frac{5}{a}....eqn(i) \\ \\ new \: resistance \: ➪ \: R` = ρ\times \frac{2.5}{2a}....eqn(ii) \\ \\ on \: dividing \: eqn(ii) \: by \: eqn(i)... \\ \\ \frac{R`}{2} = \frac{2.5ρ}{2a} \div \frac{5ρ}{a} = \frac{1}{4} \\ \\ R` = \frac{2}{4} = 0.5 \: Ω[/tex]
Thus, on doubling the wire on itself, its resistance becomes one-fourth.
Hope it helps you!!A 20m long string has mass of 0.020kg .if 5.0m segment of the string is fixed at both ends and three loops are produced when a force of 10N is applied to the string .calculate the velocity and frequency of the standing wave of the string
Answer:
.
Explanation:
HELP PLS! Mrs. Frazier was on a jet ski traveling 25 km/min NE in Lake Norman last weekend. She started slower at 5 km/min but within 5 mins she had increased her speed. What was her acceleration?
21 km/hr
4 km/min2
100 km/min
6.2 km/hr
Answer:
4 km/min^2
Explanation:
acceleration is the rate of change of speed per time
25 -5 = 20 km/min speed change
20 km/min / 5 min = 4 km /min^2
Question 4 of 10
A person suffering from PTSD:
A. may have flashbacks and feel anxious.
B. may wash his hands hundreds of times a day.
C. cannot remember what happened to him.
O D. cannot be successful.
Obtain the potential on the x-axis at x = 0 for the following point charge distributions on the x-axis: 200 μC at x = 20 cm, -300 μC at x = 30 cm and -400 μC at x = 40 cm.
The eletric potential on the x - axis at x = 0 cm for the given three charges is determined as 9 x 10⁶ V.
Electric potentialThe electric potential at a point is the work done in moving a test charge from infinity to a certain point.
Eletric potential at x = 0 cmV(net) = V1 + V2 + V3
[tex]V = - \frac{kq}{r} \\\\V(net) = V_1 + V_2 + V_3\\\\V_{(net)} = -\frac{9\times 10^9 \times 200\times 10^{-6}}{0.2} + \frac{9\times 10^9 \times 300\times 10^{-6}}{0.3}+ \frac{9\times 10^9 \times 400\times 10^{-6}}{0.4}\\\\V_{(net)} = -9\times 10^6 \ + \ 9\times 10^6 \ + \ 9\times 10^6 \\\\V_{(net)} = 9\times 10^6 \ V[/tex]
Thus, the eletric potential on the x - axis at x = 0 cm for the given three charges is determined as 9 x 10⁶ V.
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A rugby player sits on a scrum machine that weighs 200 Newtons. Given that the coefficient of static friction is 0.67, the coefficient of kinetic friction is 0.56 and the force required to push both the scrum machine and the player into motion is 850 Newtons, calculate the following: a) The mass of the player ( 4marks) b) The magnitude of the force required to keep both the scrum machine and the player in motion?
a. 850 N is the minimum force needed to get the machine/player system moving, which means this is the maximum magnitude of static friction between the system and the surface they stand on.
By Newton's second law, at the moment right before the system starts to move,
• net horizontal force
∑ F[h] = F[push] - F[s. friction] = 0
• net vertical force
∑ F[v] = F[normal] - F[weight] = 0
and we have
F[s. friction] = µ[s] F[normal]
It follows that
F[weight] = F[normal] = (850 N) / (0.67) = 1268.66 N
where F[weight] is the combined weight of the player and machine. We're given the machine's weight is 200 N, so the player weighs 1068.66 N and hence has a mass of
(1068.66 N) / g ≈ 110 kg
b. To keep the system moving at a constant speed, the second-law equations from part (a) change only slightly to
∑ F[h] = F[push] - F[k. friction] = 0
∑ F[v] = F[normal] - F[weight] = 0
so that
F[k. friction] = µ[k] F[normal] = 0.56 (1268.66 N) = 710.45 N
and so the minimum force needed to keep the system moving is
F[push] = 710.45 N ≈ 710 N
Which of the following is not part of the control system? steering wheel exhaust pipe brake accelerator
Answer:
Brakes unevenly adjusted: Brakes pulling in one direction or the other can lead to a skid. Tires with worn tread: Tread is necessary for traction in wet weather
Explanation:
Answer: exhaust pipe
Explanation: It doesn't really control anything so I'm assuming this is the answer
Which definition refers to electrical power?
A. The rate at which an electric charge flows past a point in a circuit
B. The energy of an electric charge minus the resistance in a circuit
C. The energy of an electric charge due to its position in an electric
field
D. The rate at which electrical energy is transferred in a circuit
In which of the following situations would an electromagnet be more useful than a magnet? *
1 point
A teacher uses a magnet to attach their name tags to her shirt.
B child is linking magnetic balls together to make a necklace.
C parent is hanging up a good grade on a refrigerator.
D scrapyard worker is sorting car parts.
The answer to your question is: C
Your bicycle has a
mass of 7 kg. You
accelerate at a rate of
2.45 m/s2. What is the
net force?
Answer:
17.15 N
Explanation:
Remember F = m a
= 7 kg * 2.45 m/s^2 = 17.15 N
Identify a scenario from
gym class that has an action-reaction force. Describe the situation
Answer:
A person is doing push-ups against a wall (action force), and the wall exerts an equal and opposite force against the person (reaction force).
Explanation:
what is the principle of simple machine?
Answer:
The principle of simple machine states that "if there is no friction in a simple machine, work output and work input are found equal in that machine.
Explanation:
Answer:
Usually, the term refers to the six classical simple machines which were defined by Renaissance scientists:
LeverWheel and axlePulleyInclined planeWedgescrewAlso, a simple machine uses a single applied force to do work against a single load force.