The radioactivity due to carbon-14 measured in a piece of a wood from an ancient site was found to produce 20 counts per minute from a given sample, whereas the same amount of carbon from a piece of living wood produced 160 counts per minute
The half-life of carbon-14, a beta emitter, is 5730 y. The age of the artifact is closest to
A) 5700 y.
B) 12,000 y.
C) 15,000 y.
D) 17,000 y.
E) 23,000 y.
Answer: D
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Standing Sound Waves: An pipe of length L that is open at both ends is resonating at its fundamental frequency. Which statement about the sound is correct?
A. The wavelength is 2L and there is a displacement node at the pipe's midpoint. B. The wavelength is 2L and there is a displacement antinode at the pipe's midpoint. C. The wavelength is L and there is a displacement node at the pipe's midpoint. D. The wavelength is L and there is a displacement antinode at the pipe's midpoint.
Using the information in figure 1.23 what is the distance to the nearest CM in the triangle at the right?
A. 26 cm B. 20 cm C. 17 cm D. 15 CM
Passengers in a high-flying jumbo jet feel their normal weight in flight, whereas passengers in an orbiting space vehicle do not because they are
A) beyond the main pull of Earth's gravity. B) above the Earth's atmosphere. C) without support forces. D) all the above E) none of the above
What resolving power must a diffraction grating have in order to distinguish wavelengths of 686.30 nm and 687.50 nm? (1 nm = 10?9 m)
a. 343 b. 572 c. 686.9 d. 915 e. 687.5