If a sunspot has a temperature of 4,500 K and the surrounding solar surface has a temperature of 5,800 K, how many times brighter is the surface compared to the sunspot?
a. 0.28
b. 0.36
c. 2.8
d. 3.6
e. 36
c
You might also like to view...
What observations suggest the mass of the Galaxy goes much farther out than its visible disc?
A) the rotation curve of the outermost portions of the disc B) 21-cm maps of the spiral arms C) infrared observations of distant brown dwarfs D) the orbits of the open clusters in the disc E) X-ray images of other galaxies' discs from Chandra
Early human culture, involving villages and a sense of history, could best be described as a(n)
A) industrial culture. B) migratory culture. C) hunting culture. D) scientific culture. E) agri-culture.
Air is pumped into a bicycle tire at constant temperature. The pressure increases because:
A. more molecules strike the tire wall per second B. the molecules are larger C. the molecules are farther apart D. each molecule is moving faster E. each molecule has more kinetic energy
Potential of Point-Charges: The three point charges shown in the figure form an equilateral triangle with sides 4.9 cm long. What is the electric potential (relative to infinity) at the point indicated with the dot, which is equidistant from all three charges? Assume that the numbers in the figure are all accurate to two significant figures. (k = 1/4??0 = 9.0 × 109 N ? m2/C2)
A. 0.00 V B. 1300 V C. 640 V D. 1900 V