I need help with this one

An electron in the n = 7 level of the hydrogen atom relaxes to a lower energy level, emitting light of 397 nm. what is the value

Dimas [21]

Answer:

$n_f=2$

Explanation:

It is given that,

Initially, the electron is in n = 7 energy level. When it relaxes to a lower energy level, emitting light of 397 nm. We need to find the value of n for the level to which the electron relaxed. It can be calculate using the formula as :

$\dfrac{1}{\lambda}=R(\dfrac{1}{n_f^2}-\dfrac{1}{n_i^2})$

$\dfrac{1}{397\times 10^{-9}\ m}=R(\dfrac{1}{n_f^2}-\dfrac{1}{(7)^2})$

R = Rydberg constant, $R=1.097\times 10^7\ m^{-1}$

$\dfrac{1}{397\times 10^{-9}\ m}=1.097\times 10^7\ m^{-1}\times (\dfrac{1}{n_f^2}-\dfrac{1}{(7)^2})$

Solving above equation we get the value of final n is,

$n_f=2.04$

or

$n_f=2$

So, it will relax in the n = 2. Hence, this is the required solution.

6 0

3 years ago

Read 2 more answers

A steel rod is pulled in tension with a stress that is less than the yield strength. The modulus of elasticity may be calculated

pshichka [43]

Answer:

B. Axial stress divided by axial strain

Explanation:

Elasticity:

It is the tendency of an object to deform along the axis when an opposing force is applied without facing permanent change in shape.

Plasticity:

When an object crosses the elasticity limit, it enters plasticity where the change due to stress is permanent and the object might even break.

Yield strength:

Yield strength is the point of maximum bearable stress that indicates the limit of elasticity.

Our case:

As the stress applied is less than the yield strength, the rod is still in the elasticity state and its modulus can be calculated.

Modulus of Elasticity = Stress along axis/Ratio of change in length to original length

Axial strain is basically the ratio of change in length to original length.

So, Modulus of Elasticity = Axial Stress/ Axial Strain

6 0

3 years ago

Ball A is negatively charged and ball B is electrically neutral. What happens to the charges of both balls when they come into c

tresset_1 [31]

Explanation:

They will repel, thus made of electrical conductor.

5 0

2 years ago

True or false radiant energy spreads out from its source in all directions

Sati [7]

Well the Answer is True.

6 0

2 years ago

If, as is typical, each of them breathes about 500 cm3 of air with each breath, approximately what volume of air (in cubic meter

deff fn [24]

Answer:

a) 12614.4 m^3

b) 28.8 m

Explanation:

The complete question is

Four astronauts are in a spherical space station. (a) If, as is typical, each of them breathes about 500 cm^3 of air with each breath, approximately what volume of air (in cubic meters) do these astronauts breathe in a year? (b) What would the diameter (in meters) of the space station have to be to contain all this air?

The average breathing rate is 12 breaths per minute

there are 60 minutes x 24 hours x 365 days in a year = 525600 minutes in a year

if an average human takes 12 breath per minute, then in a year an average human take 12 x 525600 = 6307200 breath

For the four astronauts, the amount of breath = 4 x 6307200 = 25228800 breath in total.

The volume of air per breath = 500 cm^3

1 cm^3 = 10^-6 m^3

500 cm^3 = $x$ m^3

$x$ = 500 x 10^-6 = 5 x 10^-4 m^3

Therefore in a year, the volume of these astronauts breath in a year = 5 x 10^-4 x 25228800 = 12614.4 m^3

b) If the space station is spherical, the volume will be given as = $\frac{4}{3} \pi r^3$

where r is the radius of the space station

This volume of the space station must be able to contain all the volume of breath produced by the astronauts which is = 12614.4 m^3

Equating, we have

12614.4 = $\frac{4}{3} \pi r^3$

12614.4 = $\frac{4}{3}*3.142*r^3$

12614.4 = 4.1893 $r^{3}$

$r^{3}$ = 12614.4/4.1893 = 3011.1

r = $\sqrt[3]{3011.1}$ = 14.4 m

diameter of the space station = 14.4 m x 2 = 28.8 m

3 0

3 years ago