Rotation curves for spiral galaxies show
A) they are slowing down.
B) most have dark halos.
C) rotation speed drops off further from the nucleus.
D) most of the mass lies in the nucleus.
E) no relation to mass.
B
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The Lyman series of hydrogen is made up of those transitions made from higher levels to n = 1 . If the fifth line in this series has a wavelength of 94 nm, what is the wavelength of the sixth line?
a. 106 nm b. 93 nm c. 117 nm d. 102 nm e. 124 nm
The planets of the solar system were formed:
a) by the collapse of a single higher mass star into a black hole b) by a near collision between the Sun and a nearby star c) as condensations/accretions of hot gases ejected from the Sun d) by the accumulation of many comets e) as individual condensation/accretion centers in a rotating solarnebula
Consider a system containing three objects that move with different velocities. The objects can interact with each other through forces. In this system
A. the objects can only collide if an outside force is applied. B. any collisions between the objects must be elastic. C. the total momentum of the objects cannot change unless an outside force acts on the system. D. the total kinetic energy of the objects will not change unless an outside force is applied.
Compared to a hydrogen atom where the proton and electron both have spin in the same direction, an atom where they spin in opposite directions will have ________ energy
Fill in the blank(s) with correct word