Why does the Sun brighten with time?
A) as time progresses, helium starts to fuse in the core, in addition to hydrogen, leading to an increase in brightness
B) as hydrogen is converted into helium in the core, the number of hydrogen nuclei decreases, decreasing the fusion rate. To maintain the balance with gravity pressing inward, the core compensates by shrinking and heating up
C) as time progresses, more and more heat is trapped inside the core, leading to an increase in brightness
D) as hydrogen is converted into helium in the core, the number of hydrogen nuclei decreases, decreasing the fusion rate. To maintain the balance with gravity pressing inward, the core compensates by expanding and cooling
B
You might also like to view...
Free Fall: Abby throws a ball straight up and times it. She sees that the ball goes by the top of a flagpole after 0.50 s and reaches the level of the top of the pole after a total elapsed time of 4.1 s. What was the speed of the ball at launch? Neglect air resistance.
A. 11 m/s B. 23 m/s C. 34 m/s D. 45 m/s E. 48 m/s
The frequency of a light beam is doubled. Which one of the following is correct for the momentum of the photons in that beam of light?
A) It stays the same. B) It is halved. C) It is doubled. D) It is reduced by one-fourth E) It is quadrupled.
A stopping potential of 3.2 V is needed for radiation whose wavelength is 200 nm. What is the work function (in eV) of the material?
a. 4.0 b. 3.0 c. 5.0 d. 6.0 e. 2.0
A constant magnetic field of 0.50 T is applied to a rectangular loop of area 3.0 × 10-3 m2. If the area of this loop changes from its original value to a new value of 1.6 × 10-3 m2 in 1.6 s, what is the emf induced in the loop?
A) 1.6 × 10-2 V B) 0 V C) 7.5 × 10-2 V D) 4.4 × 10-4 V E) 9.0 × 10-2 V