Why don't we see hydrogen Balmer lines in the spectra of stars with temperatures of 3,200 K?
a. There is no hydrogen in stars this cool.
b. The stars are hot enough that most of the hydrogen is ionized and the atoms cannot absorb energy.
c. These stars are so cool that nearly all of the hydrogen atoms are in the ground state.
d. Stars of this temperature are too cool to produce an absorption spectrum.
e. Stars of this temperature are too hot to produce an absorption spectrum.
c
You might also like to view...
Regarding the relation between acceleration, force, and mass, an object's acceleration is
A) inversely proportional to the force on it and proportional to the object's mass. B) proportional to the inverse of the height of the Empire State Building. C) proportional to the force on it and inversely proportional to the object's mass. D) proportional to the force on it and proportional to the object's mass. E) inversely proportional to the force on it and inversely proportional to the object's mass.
A hoop (I = MR2) is rolling along the ground at 10 m/s. It comes to a hill and starts going up. Assuming no losses to friction, how far does it travel vertically up the hill before it stops?
a. 10 m c. 5.1 m b. 3.7 m d. 7.7 m
If a neutral atom loses one electron, what is the electrical charge of the atom?
A) -1 B) +1 C) -2 D) +2 E) neutral
The most common form of lightning strike from a cloud to the ground involves negative charge moving from the cloud to the ground. Just before a lightning strike,
A. the electric field must point toward the sky. B. the potential must be larger near the cloud. C. there are no charges on the ground. D. the potential energy of the electrons in the cloud must be small.