Interference: Two beams of coherent light start out at the same point in phase and travel different paths to arrive at point P. If the maximum destructive interference is to occur at point P, the two beams must travel paths that differ by
A. a whole number of wavelengths.
B. an odd number of half-wavelengths.
C. a whole number of half-wavelengths.
Answer: B
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How did astronomers discover the relationship between spectral type and mass for main sequence stars?
a. by measuring stellar radii with very powerful optical telescopes b. by measuring stellar radii with very powerful radio telescopes c. by comparing stars with the same spectral type but different luminosities d. by using computer models of hydrogen fusion and stellar structure e. by measuring the masses and spectral types of main-sequence stars in binary systems
Potential: As a proton moves in a direction perpendicular to the electric field lines
A. it is moving from low potential to high potential and gaining electric potential energy. B. it is moving from low potential to high potential and losing electric potential energy. C. it is moving from high potential to low potential and gaining electric potential energy. D. it is moving from high potential to low potential and losing electric potential energy. E. both its electric potential and electric potential energy remain constant.
Which of the following telescopes must be used above Earth's atmosphere?
a. an optical telescope b. the VLBA telescope c. an X-ray telescope d. a radio telescope e. None of the other choices are correct.
A convex lens is placed on a flat glass plate and illuminated from above with monochromatic red light. When viewed from above, concentric bands of red and dark are observed
What does one observe at the exact center of the lens where the lens and the glass plate are in direct contact? A) a bright red spot B) a dark spot C) a rainbow of color D) a bright spot that is some color other than red