One of the radioactive isotopes that fell on the land and got into the food chain after the Chernobyl accident was 131I. Its half-life is 8 days
How long was it, following its deposit on the land, before its radioactivity had fallen to 1/32--about 3%--of its initial value?
A) 16 days
B) several years
C) 48 days
D) 40 days
E) It is impossible to say, even approximately.
D
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According to quantum theory, the electron in a particular quantum state of the hydrogen atom has
A) a definite position. B) a definite energy. C) a definite velocity. D) All of the above. E) None of the above.
A sound source of frequency 1 100 Hz moves at 40.0 m/s toward a listener who is at rest. What is the apparent frequency heard by the listener? (speed of sound = 340 m/s)
a. 1 230 Hz b. 970 Hz c. 980 Hz d. 1 250 Hz e. 870 Hz
Young's Modulus: A cable is 100-m long and has a cross-sectional area of 1.0 mm2. A 1000-N force is applied to stretch the cable. Young's modulus for the cable is 1.0 × 1011 N/m2. How far does the cable stretch?
A. 0.010 m B. 0.10 m C. 1.0 m D. 10 m
The graph in the figure shows the electric field strength (not the field lines) as a function of distance from the center for a pair of concentric uniformly charged spheres
Which of the following situations could the graph plausibly represent? (There may be more than one correct choice.) A) a positively charged conducting sphere within another positively charged conducting sphere B) a positively charged conducting sphere within an uncharged conducting sphere C) a solid nonconducting sphere, uniformly charged throughout its volume, inside of a positively charged conducting sphere D) a positively charged nonconducting thin-walled spherical shell inside of a positively charged conducting sphere E) a positively charged nonconducting thin-walled spherical shell inside of another positively charged nonconducting thin-walled spherical shell