The material used in certain nuclear bombs is 239Pu, which has a half-life of about 20,000 years. How long must we wait for a buried stockpile of this substance to decay to 4.0% of its original 239Pu mass?
A) 93,000 y
B) 64,000 y
C) 45,000 y
D) 800 y
Answer: A
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An adiabatic free expansion of a gas in a thermally isolated container is not reversible because
a. work must be done on the gas to return it to its original volume. b. heat must be exchanged with the surroundings to return the gas to its original temperature. c. its internal energy has a greater value after the expanded gas is returned to its original volume and temperature. d. of all of the above. e. of (a) and (b) above only.
Compound Microscope: Which one of the following statements is correct?
A. The image formed by the objective of a microscope is smaller than the object. B. The image formed by the objective lens of a telescope is larger than the object. C. The image formed by the eyepiece is real for both a microscope and a telescope. D. The image formed by the objective lens of a microscope is larger than the object.
The specific heat of a polyatomic gas is greater than the specific heat of a monatomic gas because:
A. the polyatomic gas does more positive work when energy is absorbed as heat B. the monatomic gas does more positive work when energy is absorbed as heat C. the energy absorbed by the polyatomic gas is split among more degrees of freedom D. the pressure is greater in the polyatomic gas E. a monatomic gas cannot hold as much heat
Monochromatic light hits a piece of glass. Assuming the frequency remains constant, what happens to the wavelength in the glass as the index of refraction decreases?
a. decreases c. increases b. approaches 3 × 10^8 m d. remains constant