List at least three qualities that make an astronomical object a good standard candle
What will be an ideal response?
All standard candles must have some observable property that allows us to recognize the object as a member of the unique class. For example, Cepheids vary in brightness in a characteristic way, allowing us to distinguish them from other stars; white dwarf supernova have a unique light-curve that allows us to distinguish them from massive star supernova. The remaining answers will vary, but some additional key properties include little statistical scatter in brightness; high luminosity so that they can be seen at a great distance; and relative commonness so that they can be found in many objects.
You might also like to view...
Explain a fundamental characteristic that differentiates conduction from convection and radiation.
What will be an ideal response?
We have a hollow metallic sphere with charge +5.0 µC and radius 5.0 cm. We insert a -10 µC charge at the center of the sphere through a hole in the surface. What charge now rests on the outer surface of the sphere?
a. +10 µC c. -5 µC b. +5 µC d. +15 µC
The number 0.003010 has
A) 7 significant figures. B) 6 significant figures. C) 4 significant figures. D) 2 significant figures.
A silicon monoxide (n = 1.45) film of 322-nm thickness is used to coat a glass camera lens (n = 1.56). What wavelength of light in the visible region (390 to 710 nm) will be most efficiently transmitted by this system? (1 nm = 10?9 m)
a. 467 nm b. 498 nm c. 623 nm d. 527 nm e. 736 nm