Luminosity (absolute brightness) of a star depends on its ________.
A. temperature and radius
B. radius and distance
C. mass and age
D. distance and mass
E. age and temperature
Answer: A
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Snell's Law: A light beam having a wavelength of 470 nm in air is directed into glycerine at an angle of 75.0° with the normal in air. Glycerine has a refractive index of 1.47. (c = 3.0 × 108 m/s)(a) What are the frequency and wavelength of the light in the glycerine?(b) What angle does the light beam make with the normal in the glycerine?
What will be an ideal response?
Hubble's constant is related to the age of the universe, but the precise relationship depends on the way in which the expansion rate changes with time. For a given value of Hubble's constant (such as 22 km/s/Mly), the age of the universe is oldest if
A) the expansion rate has been increasing with time (an accelerating universe). B) the expansion rate has remained nearly constant with time (a coasting universe). C) the expansion rate slows ever more gradually with time (a critical universe). D) the expansion rate is slowing enough that it will eventually reverse (a recollapsing universe).
A celebrating student throws a water balloon horizontally from a dormitory window that is 50 m above the ground. It hits the ground at a point 60 m from the building without appreciable air resistance
(a) What will be the horizontal component of the velocity of the balloon just before it hits the ground? (b) What will be the magnitude of the vertical velocity of the balloon just before it hits the ground?
Where does the energy come from when nuclear fission takes place?
a. From the chemical energy released by changing one element into another. b. From the kinetic energy introduced into the nucleus by the bombarding neutron. c. From the larger binding energies of the fission products of the original nucleus. d. From the mass of the neutron absorbed, which is lost as energy. e. From the electrical energy introduced into the nucleus by the bombarding neutron.