The sunspot cycle has a period of
a. 19 years.
b. 11 years.
c. 38 years.
d. 24 years.
b
You might also like to view...
Standing Sound Waves: One of the harmonics of a column of air in a tube that is open at one end and closed at the other has a frequency of 448 Hz, and the next higher harmonic has a frequency of 576 Hz. How long is the tube? The speed of sound in air is 343 m/s.
A. 1.34 m B. 0.670 m C. 0.335 m D. 1.00 m E. 2.68 m
A non-conducting sphere of radius R = 7.0 cm carries a charge Q = 4.0 mC distributed uniformly throughout its volume. At what distance, measured from the center of the sphere, does the electric field reach a value equal to half its maximum value?
A) 3.5 cm only B) 4.9 cm only C) 3.5 cm and 9.9 cm D) 3.5 cm and 4.9 cm E) 9.9 cm only
A nucleus undergoes radioactive decay, emitting a gamma ray. Which of the following statements is true?
A. A nuclear proton changes into an electron-positron pair. B. Both daughter and parent nuclei have the same atomic number. C. The daughter nucleus is more massive than the parent. D. The daughter nucleus has more neutrons than the parent.
Ethanol is to be condensed around cool 10ºC tubes of 1 cm outside diameter and at a 50 saturation temperature of 78.5ºC. Plot the heat transfer per unit length on horizontal tubes arranged as shown in Figure 10-17b and as predicted by Equation 10-49 as the number of tubes is increased. How does this result compare to the heat transfer predicted for a single tube or for a dripping, in-line tube arrangement as shown in Figure 10-17c? Ethanol has a heat of vaporization hnfg of 842 J/kg at atmospheric pressure.
