Question

a) Given that the Sun’s photosphere is at a temperature of ~6000 K, would you expect collisional or radiative excitations to be more important in exciting hydrogen atoms to the second (n=2) level?

(b) Would you expect the Lyman a (n = 1 -> 2 or 2 ->1) line to appear in emission or absorption? Justify your answer.

Answer #1

(a) in sun's photosphere where the temperature is about 6000 Kelvin ,the radiative excitations are more important than collisional (having lower energy) in exciting the electrons of hydrogen atom to n = 2 level.

(B)

lyman alpha n(1-->2) Transitions require energy to be observed, thus a line would appear as absorption spectra .

the transition n(2-->1) emits energy in the form of radiation thus will be observed as the emission spectra .

emission and absorption spectra of a same atom are like negative and positive of each other that is complementary to each other.

The wavelength of peak emission from any star is related to the
temperature of its photosphere (i.e., the emitting surface) by
Wien’s Law, given by λ = 2,900/T, where λ is the wavelength in
micrometers (1 µm = 10-6 m), and T is the temperature of the star
in Kelvin (see textbook’s figure 3.27 for help). Answer the
following questions using the above equation.
2.1. The most massive star ever observed is a Wolf-Rayet
type-star, named R136a1. It is so...

1. Calculate the energy (in kJ/mol) of the Lyman series line for
hydrogen that is, the transition from n=2 to n=1 (1 kJ/mol= 8.6
cm^-1)
2. Would you expect the energy of the same transition as in the
first problem to be greater or less for the helium ion, He^+? Why?
Make a sketch to relative scale the energy levels that give rise to
the Lyman bands in H-atoms and He^+.

Another spectral correction is due to the Doppler effect. If the
atoms you are observing are in a gas, they are likely in motion,
some moving toward you and some away. This will shift some
frequencies up and some down, making the spectral line appear to
have a width. Compute the expected Doppler broadening ?lof the
Lyman alpha line from a hot star with temperature 10,000K.
Use the fact that the average thermal kinetic energy is
given by (3/2) kT,...

What would you expect to occur if parietal cells NO LONGER
functioned?
A. there would be no carbohydrate digestion in the stomach
B. less pepsinogen would be secreted into the stomach
C. vitamin B12 could no longer be absorbed
D. the pH of the stomach would decrease
What is true about enzymes that can digest lipids?
A. all lipases are secreted as zymogens
B. gastric and lingual lipase function best in a low pH
C. all lipases begin digesting lipids...

1. Suppose that you are given a 200 gram sample of a radioactive
substance with a half-life of 45 days. How many grams will be left
after 360 days?
2. A radioactive substance is found to register 5000 counts per
second on a Geiger counter. Twenty-four hours later it registers
1250 counts per second. What is its half-life?
3. If a sample emits 2000 counts per second when the detector is
1 meter from the sample, how many counts per...

1.1 Suppose you want to make a scale model of a hydrogen atom.
You choose, for the nucleus, a small ball bearing with a radius of
[01] mm. The radius of the hydrogen atom is 0.529 × 10−10 m and the
radius of the nucleus is 1.2 × 10−15 m. (a) What would be the
radius (m) of the model? (b) Suppose that now you want to make a
scale model of the solar system using the same ball bearing...

1.) Which transition in a hydrogen atom would
emit the photon of greatest frequency?
n = 35 to n = 2
n= 6 to n = 2
n = 12 to n = 6
n = 1 to n = 4
n = 2 to n = 9
n = 3 to n = 1
***NOT n=35 to n=2***
2.) Which transition in a hydrogen atom would
absorb the photon of greatest frequency?
n = 3 to n = 1...

1.) Which transition in a hydrogen atom would
emit the photon of greatest frequency?
n = 35 to n = 2
n= 6 to n =
2
n = 12 to n =
6
n = 1 to n = 4
n = 2 to n = 9
n = 3 to n = 1
***NOT n=35 to n=2***
2.) Which transition in a hydrogen atom would
absorb the photon of greatest frequency?
n = 3 to n = 1...

11. During as assessment of a healthy adult , where would a
nurse expect to observe the apical impulse? A. Forth left
intercostal space to the sternal border B. Third left intercostal
space at the midclavicular line C. Fifth left intercostal space at
the sternal border D. Fifth left intercostal space at the
midclavicular line
12. Diaphragmatic excursion should be equal bilaterally and
measure about: A. 3-5 CM B. 3-4 CM C. 2-3 CM D. 4-5 CM
13. A nurse...

1
In the absence of
oxygen, cells consume glucose at a high, steady rate. When oxygen
is added, glucose consumption drops precipitously and is then
maintained at the lower rate. Why is glucose consumed at a high
rate in the absence of oxygen and at a low rate in its
presence?
2
In the following
diagram showing the distribution of thermal energy in a population
of substrate molecules, the energy thresholds indicated by numbers
represent ...
Energy
per molecule
Number...

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