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
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:
Consider two blocks that are attached bv a string. Block 1 (mass of 2 ko) lavs on a flat dlane. Block ? (mass of 3 kg) hangs freely off the edge of the plane. In the absence of friction, Block 2 would fall and the string would pull Block 1 towards the edge. Find the static coefficient of friction needed to keep Block at its starting position.
With no friction, block 1 would be pulled to the edge of the table as block 2 falls. By Newton's second law, the net horizontal force on block 1 is
∑ F[1, h] = T = (2 kg) a
where T = magnitude of tension and a = acceleration of the blocks, while the net force on block 2 is
∑ F[2] = (3 kg) g - T = (3 kg) a
where (3 kg) g = weight of block 2 and g = 9.8 m/s². Notice that we take the downward fall of block 2 to be the positive direction.
Eliminate T and solve for a :
T + ((3 kg) g - T) = (2 kg) a + (3 kg) a
(3 kg) g = (5 kg) a
a = 3g/5
Solve for T :
T = (2 kg) (3g/5) = 6g/5 kg = 11.76 N
Now, taking friction into account, block 1 would have net force
∑ F[1, h] = T - sf = 0
so that the maximum magnitude of static friction is sf = 11.76 N. The net vertical force on block 1 is
∑ F[1, v] = n - (2 kg) g = 0
where n = magnitude of the normal force. Let µ be the coefficient of static friction. It follows that
n = (2 kg) g = 19.6 N
sf = µ n ⇒ µ = (11.76 N) / (19.6 N) = 0.6
The rate at which an object changes position is called?
Question 5 options:
Speed
Distance
Momentum
Acceleration
Answer:
I think that it is called speed
Explanation:
Answer:
speed
Explanation:
The rate of change of POSITION is speed
The rate of change of SPEED is acceleration
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.
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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What are the uses of magnet ?
Answer:
A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials.
Answer:
Toys. Magnets are found in some toys. Compasses. In compasses, magnets are used to make sure that the needle always points north. Hospitals. In some medical processes, they use magnets. Fridge Magnets. Furniture and Household Appliances. hold Appliances. Jewellery. hold Appliances. Jewellery. Recycling.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
10. As a spaceship is moving toward Earth, an Earthling measures its length to be 325 m, while the captain on board radios that her spaceship's length is 1150 m. (c = 3.00 × 108 m/s) (a) How fast is the rocket moving relative to Earth? (b) What is the TOTAL energy of a 75.0-kg crewman as measured by (i) the captain in the rocket and (ii) the Earthling?
Answer:
Explanation:
10. As a spaceship is moving toward Earth, an Earthling measures its length to be 325 m, while the captain on board radios that her spaceship's length is 1150 m. (c = 3.00 × 108 m/s) (a) How fast is the rocket moving relative to Earth? (b) What is the TOTAL energy of a 75.0-kg crewman as measured by (i) the captain in the rocket and (ii) the Earthling?
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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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
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
help i dont understnad and its realky confusing
Answer:
See below
Explanation:
Wavelength is distance between consecutive wave crests or consecutive troughs
in this situation when one boat is at crest the other is in the trough...
the wavelength will be twice this distance between the boats
WL = 2 * 18 = 36 meters
amplitude is (distance from bottom to top) divided by two
ampl = 2.6/2 = 1.3 m (this is the same as the distance from the midline of the wave to the top of the wave)
5 cycles in 10 seconds ...the frequency is in Hz ...which is cycles per second , so the frequency = 5 cycles/ 10 seconds = .5 Hz
Period is = 1/f = 1/.5 Hz = 2 seconds per cycle
reasons of studying physics
Answer:
Physics helps you to understand the world around you, and satisfy your curiosity. It develops your critical thinking and problem-solving skills.
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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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
g A series circuit contains a 1.0-k Ω resistor, a 5.0-mH inductor, and an ideal 25-V power supply. What is the time constant for the circuit?
Hi there!
Recall the equation for an LR circuit time-constant:
[tex]\tau = \frac{L}{R}[/tex]
L = Inductance (H)
R = Resistance (Ω)
Plug in the given values.
[tex]\tau = \frac{0.005}{1000} = 0.000005 s = \boxed{\text{5 } \mu s}[/tex]
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
the moon has an orbital period of 63.3 days. Calculate the average distance from the earth
Answer:
2 pi R / T = speed of moon
m V^2 / R = G M m / R^2 centripetal force = gravitational force
V^2 / R = G M / R^2
4 pi^2 R^2 / (T^2 R) = G M / R^2 using first equation
R^3 = 1 / (4 pi^2) * G M T^2 we need to know G and M
R^3 = .0253 * 6.67E-11 * 5.98E24 T^2 = 1.01E13 * T^2
63.3 da = 5.47E6 sec
T^2 = 2.99E13 sec^2
R^3 = 1.01E13 * 2.99E13 = 3.02E26 = 302E24 m^3
R = 6.70E8 m from center of earth
Using 1609 m/mile
R = 416,000 miles
Note: our moon is about 239,00 miles away
So this distance is about 1.74 our earth-moon distance
If T^2 proportional R^3 (the moon period is 27.3 da)
63.3/27.3 = 2.32 2.32^2 = 5.38
416/239 = 1.74 1.74^3 = 5.27
Not exact but reasonably close
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.
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
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.
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.
5. A single slit illuminated with a 500 nm light gives a diffraction pattern on a far screen. The 5th minimum occurs at 7.00° away from the central maximum. At what angle does the 18th minimum occur? A) 26.0° B) 1.94° C) 5.05° D) 0.44°
For a single slit illuminated with a 500 nm light gives a diffraction pattern on a far screen,the angle is mathematically given as
theta=25.3
Option A is correct
What angle does the 18th minimum occur?Generally, the equation for the the angle is mathematically given as
[tex]\theta=n(\lambda/d)[/tex]
Therefore
[tex]\theta 1/ \theta 2=n1(\lambda/d)/ n2(\lambda/d)[/tex]
In conclusion
theta/7=16/5
theta=10*7/5
theta=25.3
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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.
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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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.
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.
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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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.
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