Studying a spectrum from a star can tell us a lot. All of the following statements are true except one. Which statement is not true?
A) The total amount of light in the spectrum tells us the star's radius.
B) The peak of the star's thermal emission tells us its temperature: hotter stars peak at shorter (bluer) wavelengths.
C) We can identify chemical elements present in the star by recognizing patterns of spectral lines that correspond to particular chemicals.
D) Shifts in the wavelengths of spectral lines compared to the wavelengths of those same lines measured in a laboratory on Earth can tell us the star's speed toward or away from us.
A
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Convection circulates gases from deep in Jupiter’s atmosphere to the top, where they
a. escape into space. b. condense and make bubbles. c. condense and make clouds. d. form plasma.
The geocentric model of the Greeks consisted of a
A) flat Earth at the center of the universe surrounded by a dome-shaped sky B) flat Earth at the center of the universe surrounded by a celestial sphere C) spherical Earth at the center of the universe surrounded by a dome-shaped sky D) spherical Earth at the center of the universe surrounded by a celestial sphere
In the potential energy diagram of a molecule, the activation energy is the energy that is
A) necessary to get the molecule to form. B) above the ground state of the molecule. C) released when the molecule is formed. D) stored in the molecule. E) at the ground state of the molecule.
What is the equivalent resistance between points A and B in the figure when R = 20 ??
a.
77 ?
b.
63 ?
c.
70 ?
d.
84 ?
e.
140 ?