what is the energy (in j) of a photon required to excite an electron from n = 2 to n = 8 in a he⁺ ion? submit an answer to three signficant figures.
Answer:
Approximately [tex]5.11 \times 10^{-19}\; {\rm J}[/tex].
Explanation:
Since the result needs to be accurate to three significant figures, keep at least four significant figures in the calculations.
Look up the Rydberg constant for hydrogen: [tex]R_{\text{H}} \approx 1.0968\times 10^{7}\; {\rm m^{-1}[/tex].
Look up the speed of light in vacuum: [tex]c \approx 2.9979 \times 10^{8}\; {\rm m \cdot s^{-1}}[/tex].
Look up Planck's constant: [tex]h \approx 6.6261 \times 10^{-34}\; {\rm J \cdot s}[/tex].
Apply the Rydberg formula to find the wavelength [tex]\lambda[/tex] (in vacuum) of the photon in question:
[tex]\begin{aligned}\frac{1}{\lambda} &= R_{\text{H}} \, \left(\frac{1}{{n_{1}}^{2}} - \frac{1}{{n_{2}}^{2}}\right)\end{aligned}[/tex].
The frequency of that photon would be:
[tex]\begin{aligned}f &= \frac{c}{\lambda}\end{aligned}[/tex].
Combine this expression with the Rydberg formula to find the frequency of this photon:
[tex]\begin{aligned}f &= \frac{c}{\lambda} \\ &= c\, \left(\frac{1}{\lambda}\right) \\ &= c\, \left(R_{\text{H}}\, \left(\frac{1}{{n_{1}}^{2}} - \frac{1}{{n_{2}}^{2}}\right)\right) \\ &\approx (2.9979 \times 10^{8}\; {\rm m \cdot s^{-1}}) \\ &\quad \times (1.0968 \times 10^{7}\; {\rm m^{-1}}) \times \left(\frac{1}{2^{2}} - \frac{1}{8^{2}}\right)\\ &\approx 7.7065 \times 10^{14}\; {\rm s^{-1}} \end{aligned}[/tex].
Apply the Einstein-Planck equation to find the energy of this photon:
[tex]\begin{aligned}E &= h\, f \\ &\approx (6.6261 \times 10^{-34}\; {\rm J \cdot s}) \times (7.7065 \times 10^{14}\; {\rm s^{-1}) \\ &\approx 5.11 \times 10^{-19}\; {\rm J}\end{aligned}[/tex].
(Rounded to three significant figures.)
the gravitational force acts on all objects in proportion to their mass. neglecting air resistance, why don’t heavy objects fall faster than light ones?
Answer:
Because in correspondence to the same distance from a mass, the gravitational acceleration is the same for all the bodies. It doesn't depend on the mass of the objects.
Before Collision:
2,000 kg 4 m/s 4,000kg 0 m/s
After collision: 2,000 kg + 4,000kg Vt = ?
I will give Brainliest to the first person. Please show work
Answer:
4/3 m/s
Explanation:
Assuming momentum is conserved, the sum of products of mass and speed before the collision is the same as after:
(2000 kg)(4 m/s) +(4000 kg)(0 m/s) = (2000 +4000 kg)(Vt)
Vt = (8000 kg·m/s)/(6000 kg) = 4/3 m/s
The speed of the combined objects after the collision is 4/3 m/s.
Elliot jumps up and down on a pogo stick. He weighs 600.N, and his pogo stick has a spring with spring constant 1100N/m. What is the height he will reach when he has gravitational potential energy 250J? m
From conservation of energy, the height he will reach when he has gravitational potential energy 250J is 0.42 meters approximately
The given weight of Elliot is 600 N
From conservation of energy, the total mechanical energy of Elliot must have been converted to elastic potential energy. Then, the elastic potential energy from the spring was later converted to maximum potential energy P.E of Elliot.
P.E = mgh
where mg = Weight = 600
To find the height Elliot will reach, substitute all necessary parameters into the equation above.
250 = 600h
Make h the subject of the formula
h = 250/600
h = 0.4167 meters
Therefore, the height he will reach when he has gravitational potential energy 250J is 0.42 meters approximately
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Can someone please give me the (Answers) to this? ... please ...
Answer:
Jake’s horse will only need to exert enough force to make the carriage accelerate. Even though the carriage will pull on the horse as well, that force is not enough to make the horse accelerate in the direction of the carriage because it is only strong enough to make the carriage accelerate, not the horse.
Explanation:
Additional info: the horse has more mass than the carriage does so it would require a stronger force to make the horse accelerate.
Answer: Jake’s horse will only need to exert enough force to make the carriage accelerate .Since the horse has a greater mass than the carriage, it requires a stronger force to make the horse accelerate.
Explanation: Sorry it took so long lol
how long does it take a man to travel 6 km if his speed is 3km/h?
why did my answer get deleted??
oh yeah i put a link on there- oopsies.
I wont this time!
I got 30!
what is the velocity of a 50 kg dog with 3000 j of kinetic energy
Answer:
KE = 225000000 J
Explanation:
Answer:
10.954. from equation. KE=1/2m(v^2)
2KE=m(v^2) 6000=50(v^2) (v^2)=6000/50
(v^2)=120. square root for all v=10.954 m/s
Calculate the resistance of a 1km length, 1mm diameter wire made from:
a) constantan (\rho = 4.9 × 10-7 Ωm)
b) copper (\rho = 1.7 × 10-8 Ωm)
c) State which material is better suited for being used to make resistors, and justify your answer.
d) With 1 amp of current flowing through each of the wires how much energy is converted to heat?
e) What potential difference would be needed to force a current of 1 amp through that length of each type of wire?
From the values of resistivity, the resistance of copper wire is 22 Ω.
Let us recall that;
R = ρl/A
ρ = resistivity
l = length of the wire
A = cross sectional area of the wire
For constantan;
R = 4.9 × 10^-7 × 1 × 10^3/[3.14 × ((1 × 10^-3)/2)^2]
R = 620 Ω
For copper;
R = 1.7 × 10-8 × 1 × 10^3/[3.14 × ((1 × 10^-3)/2)^2]
R = 22 Ω
The material that is best suitable to make resistors is constantan wire.
For constantan, the energy converted to heat is;
I^2 R = (1)^2 × 620 Ω = 620 W
For copper, the energy converted to heat is;
I^2R = (1)^2 × 22 Ω = 22Ω
The potential difference of constantan = IR = 1 × 620 Ω = 620 V
The potential difference of copper = = IR = 1 × 22Ω = 22 V
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During which time does Jamal have the greatest momentum?
Answer:
Momentum Packet Answer KEY - Science Online
YOU WILL SEE THE PDF
A student noted that the sign shown here is always associated with a wheelchair ramp at or near a staircase or entrance steps. What statement best identifies the reason why wheelchair ramps are used to move people up a staircase or steps?
The main reason why wheelchair ramps are used to move people up a staircase is because it has a high mechanical advantage which leads to a greater efficiency in moving people up the staircase.
Let the height of the staircase = hLet the length of the ramp = L
The mechanical advantage of the ramp is calculated as follows;
[tex]M.A = \frac{L}{h}[/tex]
As the length of the ramp increases, people will be move up to a greater distance up the staircase.
Thus, the main reason why wheelchair ramps are used to move people up a staircase is because it has a high mechanical advantage which leads to a greater efficiency in moving people up the staircase.
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What happens to all light bulbs in a series circuit when one burns out? How would the situation change when the lights are hooked up in parallel?
The Doppler technique for planet detection has found Earth-like planets around nearby Sun-like stars. (True or False) ____________________
Answer: false
Explanation:
Draw a nitrogen cycle and explain in short.
please help me
Answer: biogeochemical process
Explanation:
Line segment Q R , Line segment R S and Line segment S Q are midsegments of Î"WXY. Triangle R Q S is inside triangle X Y W. Point R is the midpoint of side X Y, point S is the midpoint of side Y W, and point Q is the midpoint of side X W. The length of Q R is 2. 93 centimeters, the length of R S is 2. 04 centimeters, and the length of Q S is 2. 28 centimeters. What is the perimeter of Î"WXY? 11. 57 cm 12. 22 cm 12. 46 cm 14. 50 cm.
The perimeter of ΔWXY is : ( D ) 14.5 cm
Calculating the perimeter of ΔWXY
QR = WY / 2
RS = XW / 2
QS = XY / 2
Given that : QR = 2.93 cm , RS = 2.04 cm, QS = 2.28 cm
Therefore
Perimeter of ΔWXY = ∑ WY + XW + XY
= 2SR + 2QS + 2QR
= 2(2.04) + 2(2.28) + 2(2.93)
= 14.5 cm
Hence we can conclude that the perimeter of ΔWXY = 14.5 cm
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Answer:
The name of the shape on the right is M prime N prime O prime P prime Q prime R prime S prime because it is the image of the shape on the left.
Explanation:
what is the theory relativity by Einstein?
:MAIN ANSWER:
determined that the laws of physics are the same for all non-accelerating observers
Explanation:
Albert Einstein, in his theory of special relativity, determined that the laws of physics are the same for all non-accelerating observers, and he showed that the speed of light within a vacuum is the same no matter the speed at which an observer travels, according to Wired.
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0. Kedija walked 300m from A to B and returned back and walked 200m and then stopped at 'C', what
is her change in position from A to in the figure below
300m
200m
A
С
B
C/-500m
D 100m
B/ -100m
A Soom
Answer:
100
Explanation:
Displacement is the shortest line between the starting point and the ending point
so , the starting point is "A"
,the ending point is "C"
so "AC" = AB - CB = 300 - 200 = "100"
A textbook is sitting at rest on a desk. Compared to the magnitude of the force of the textbook on the desk, how
would you describe the magnitude of the force of the desk on the book?
o less
O zero
O more
O equal
if a 1000kg car goes from a speed of 6.5 m/s to a stop in 3 seconds what is the force acting on the car
Answer:
-6500N
Explanation:
F = ma
Note: 1N = 1 kg⋅m⋅s−2
a = (0-6.5m/s)/3s
a = -6.5m/s^2
F = 1000kg(-6.5m/s^2)
F = -6500kgm/s^2
F = -6500 N
A car takes off from rest takes of from rest and covers a distance of 80m on a straight road in 10s.Calculate the magnitude of its acceleration.
Answer:
The magnitude of its acceleration is 1.6 m/s^2.
Hope you could get an idea from here.
Doubt clarification - use comment section.
What is the main force that must be overcome in order to push an object along a horizontal surface. no silly answers
Answer:
Frictional force
Explanation:
The force that must be overcome in order to push an object along a horizontal surface is frictional force
If the force is more than frictional force the object moves
2. Think about an activity you may have learned that involves muscle memory. Consider when you first learned the activity, how easy or difficult it was the first time, and if you can do it now without thinking. What happened in your brain during practices that resulted in muscle memory for you?
Answer:
Muscle memory is found in many everyday activities that become automatic and improve with practice, such as riding bicycles, driving motor vehicles, playing ball sports, typing on keyboards, entering PINs, playing musical instruments, poker, martial arts, and dancing.
Explanation:
what is a joule in physics?
Explanation:
Joule is unit of work or energy in the International System of Units (SI)
[tex] \large \mathfrak {Formula}[/tex]
work (joules) = force (newtons) x distance (meters)
[tex] \large\mathfrak{Invented \: by} [/tex]
James Prescott Joule
A diffraction grating is 1.50 cm wide and contains 2000 lines. When used with light of a certain wavelength, a third-order maximum is formed at an angle of 20.0°. What is the wavelength (in nm)?
Answer:
because of the gravity of the earth
A wave has wavelength of 10 m and a speed of 340 m/s. What is the frequency of the wave?
I need the Formula,Known,Substitute & Solve Answer with Units
Answer:
This is the answer that I got.
Explanation:
Hope it is right.
Two students are sitting on a see-saw. The length of the board is 2 meters with the
pivot point being in the very center. One student sitting on the end of the left side
has a mass of 34 kg. If the student sitting on the right has a mass of 42.5 kg, where
should she sit for the see-saw to be in equilibrium?
To solve the problem it is necessary to apply the concepts of Torque and equilibrium.
The Torque is defined as:
Where
F= Force
d = Distance
In this particular case, the force is caused by the weight of both children.
In turn, when there is equilibrium, the two torques must be equal therefore
Replacing with our values
Re-arrange to find
Therefore the distance that the second kid should sit to balance the see-saw is 1.8m from the pivot.
how to find velocity with constant acceleration
Answer:
velocity = distance / time
example:
if a body moves "20" meters in "2" seconds
, then it's velocity = 20/2 = "10m/s"
The definition of energy is the ability to ___________.
(Hint: one word)
a plane mirror forms a virtual image why
A car is being towed. What is the car’s
mass if the net force on the car is 4,000 N and it has an
acceleration of 2.5 m/s^2?
Mass of the car having acceleration 2.5 m/s² and net force 4000 N is 1600 kg.
What is force ?A physical cause that can change the state of motion or rest of a body is called force. It is the product of mass and acceleration off the body.
Here,
Net force acting on the car, F = 4000 N
Acceleration of the car, a = 2..5 m/s²
We know that,
F = ma
So, m = F/a
m = 4000/2.5
m = 1600 kg
Hence,
Mass of the car having acceleration 2.5 m/s² and net force 4000 N is 1600 kg.
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How many cm3 are there in 1 dm3?
The answer is in the picture.