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lawyer [7]
3 years ago
8

A singly ionized helium atom is in the ground state. It absorbs energy and makes a transition to the n = 3 excited state. The io

n returns to the ground state by emitting two photons. What are their wavelengths?
Physics
1 answer:
IRISSAK [1]3 years ago
7 0

Answer:

\lambda=25.6nm

Explanation:

The Rydberg formula can be extended for use with any hydrogen-like chemical elements, that is to say with only one electron being affected by effective nuclear charge. So, in this case, we can calculate the wavelenghts of the emitted photons using this formula:

\frac{1}{\lambda}=RZ^2(\frac{1}{n_1^2}-\frac{1}{n_2^2})

Where R is the Rydberg constant of the element, Z its atomic number, n_1 is the lower energy level and n_2 the upper energy level of the  electron transition. Recall that the ground state is denoted as n=1.

\frac{1}{\lambda}=1.1*10^7m^{-1}(2)2^2(\frac{1}{1^2}-\frac{1}{3^2})\\\frac{1}{\lambda}=3.91*10^7m^{-1}\\\lambda=2.56*10^{-8}m=25.6nm

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Speed = Distance ÷ Time
Speed = 116 ÷ 29
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Once again we have a skier on an inclined plane. The skier has mass M and starts from rest. Her speed at the bottom of the slope
mars1129 [50]

Answer:

v = 31.3 m / s

Explanation:

The law of the conservation of stable energy that if there are no frictional forces mechanical energy is conserved throughout the point.

Let's look for mechanical energy at two points, the highest where the body is at rest and the lowest where at the bottom of the plane

Highest point

       Em₀ = U = m g y

Lowest point

     Em_{f} = K = ½ m v²

As there is no friction, mechanical energy is conserved

       Em₀ = Em_{f}

       m g y = ½ m v²

       v = √ 2 g y

Where we can use trigonometry to find and

       sin 30 = y / L

       y = L sin 30

Let's replace

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Let's calculate

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3 years ago
Bridget is riding her bicycle up a hill. Which statements are correct? Check all that apply.
Svetlanka [38]

Answer:

Bridget is transferring energy to the bicycle.

The bicycle is using energy to do work.

Bridget has kinetic energy.

The bicycle has potential energy.

The bicycle has mechanical energy.

Explanation:

Energy can be transformed from one form to another. A body possess kinetic energy due to virtue of its motion. Potential energy is possessed by a body due to virtue of its position. mechanical energy is the sum of potential energy and kinetic energy. Nuclear energy is produced when atoms split or two atoms fuse together.

When Bridget is riding bicycle up a hill. Energy involved is both kinetic energy due to motion and potential energy due to gain in height up the hill. Bridget is pedaling, hence he is transferring energy to the bicycle. Bridget is in motion along with the bicycle. Hence, both Bridget and Bicycle have kinetic energy and potential energy. We can say both have mechanical energy. Thus correct options are:

Bridget is transferring energy to the bicycle.

The bicycle is using energy to do work.

Bridget has kinetic energy.

The bicycle has potential energy.

The bicycle has mechanical energy.

3 0
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Wha is amplitde in sound
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Answer:

The number of molecules displaced in a vibration makes the amplitude of a sound.

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3 years ago
A 740-kg boulder is raised from a quarry 119 m deep by a long uniform chain having a mass of 550 kg . This chain is of uniform s
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Answer:

A) the maximum acceleration the boulder can have and still get out of the quarry

B) how long does it take to be lifted out at maximum acceleration if it started from rest

Explanation:

A)

let +y is upward. look below at the free body diagram. the mass M refers to the combined mass of the boulder and chain.

the weight of the chain is:   w_{c} =m_{c} g   and maximum tension is T=2.50 m_{c} g=1.41*10^4N

total mass and weight is :

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B)

maximum acceleration

a_{y} =0.645m/s^2\\\\y-y_{0} =119m\\v_{0y} =0

using y-y_{0} =v_{oy} t+1/2(a_{y} )t^2

to solve for t

t=\sqrt{2(y-y_{0} )/a_{y} }

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