How did Harlow Shapley determine where the center of the galaxy lies?
a. He plotted the distribution of open clusters.
b. He plotted the distribution of globular clusters.
c. He made star counts in every direction of the galactic disk.
d. He measured the amount of dust obscuration in every direction of the galactic disk.
B
You might also like to view...
What element is found in all life on Earth?
a. hydrogen b. iron c. carbon d. oxygen e. nitrogen
Kepler's Laws: The average distance from Earth to the sun is defined as one astronomical unit (AU). If an asteroid orbits the sun in 1/3 of a year in a circular orbit, the asteroid's distance from the sun is closest to
A. 0.19 AU. B. 0.48 AU. C. 2.1 AU. D. 5.2 AU. E. 0.33 AU.
A 420-turn circular coil with an area of 0.0650 m2 is mounted on a rotating frame, which turns at a rate of 22.3 rad/s in the presence of a 0.0550-T uniform magnetic field that is perpendicular to the axis of rotation. What is the instantaneous emf in the coil at the moment that the normal to its plane is perpendicular to the field?
a. 33.5 V b. zero c. 0.0673 V d. 747 V e. 1.50 V
Electric Field of Point-Charges: A +5.0-?C point charge is placed at the 0 cm mark of a meter stick and a -4.0-?C charge is placed at the 50 cm mark. What is the net electric field at the 30 cm mark? (k = 1/4??0 = 8.99 × 109 N ? m2/C2)
A. 4.0 × 105 N/C B. 5.0 × 105 N/C C. 9.0 × 105 N/C D. 1.4 × 106 N/C