The brightest stars in aging globular clusters will be
A) blue supergiants like Rigel and Deneb.
B) massive blue main-sequence stars like Spica.
C) blue stragglers.
D) red supergiants like Betelgeuse and Antares.
E) core stars of planetary nebulae.
D
You might also like to view...
Which of the following transitions in hydrogen produces the photons with the longest wavelengths in the Balmer series?
1. n = 6 to n = 2 2. n = 6 to n = 3 3. n = 3 to n = 2 4. n = 2 to n = 1
A cylindrical tank is assembled by welding steel sections circumfer-entially. Tank diameter is 1.5 m, thickness is 20 mm, and internal pressure is 2.0 MPa. The maximum tensile stress in the cylindrical part of the tank is approximately:
(A) 45 MPa
(B) 57 MPa
(C) 62 MPa
(D) 75 MPa
Why do scientists say that evolution is a "theory"?
A) because it explains a great deal about life and is supported by an enormous body of evidence B) because they are not very confident that it really happened C) because it's really just a guess about how life developed on Earth D) because it is supported by only a small amount of evidence
Spherical aberration can occur in
A) mirrors and lenses. B) mirrors but not lenses. C) lenses but not mirrors.