The rate of cratering:
A) has remained constant over the last 4.6 billion years.
B) has recently increased with more collisions in the asteroid belt.
C) fluctuates over time, with massive bodies occasionally coming in from the Oort Cloud.
D) shows that large asteroid impacts are more common now than in the past.
E) shows that most interplanetary debris was swept up soon after the formation of the solar system.
E
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What is the ultimate fate of an isolated white dwarf?
A) It will cool down and become a cold black dwarf. B) As gravity overwhelms the electron degeneracy pressure, it will explode as a nova. C) As gravity overwhelms the electron degeneracy pressure, it will explode as a supernova. D) As gravity overwhelms the electron degeneracy pressure, it will become a neutron star. E) The electron degeneracy pressure will eventually overwhelm gravity and the white dwarf will slowly evaporate.
A 40-turn circular coil (radius = 4.0 cm, total resistance = 0.20 ?) is placed in a uniform magnetic field directed perpendicular to the plane of the coil. The magnitude of the magnetic field varies with time as given by B = 50 sin(10 ?t) mT where t is measured in s. What is the magnitude of the induced current in the coil at 0.10 s?
A. 50 mA B. 1.6 A C. 0.32 A D. zero E. 0.80 A
Mineral sample #1 is ____________.
Calcite - CaCO3 Dolomite - CaMg(CO3)2 Fluorite - CaF2
If the human eyeball is too short from front to back, this gives rise to a vision defect that can be corrected by using
A) convex-convex eyeglasses. B) concave-convex eyeglasses. C) cylindrical eyeglasses. D) contact lenses, but no ordinary lenses. E) shaded glasses (i.e., something that will cause the iris to dilate more).