A distant galaxy is emitting light from the helium spectrum at 388.9 nm. On Earth the wavelength of the light from this galaxy is measured to be 540.6 nm.
Estimate how far from Earth (in light-years) this galaxy is if the Hubble constant has the value 22 km/s per million light-years. (c = 3.00 108 m/s, 1 ly = 9.461 1015 m, 1 y = 3.156 107 s)
Question 2
If you take a given pendulum to the Moon, where the acceleration of gravity is less than on Earth, the resonant frequency of the pendulum will
A)
increase.
B)
decrease.
C)
not change.
D)
become zero.
E)
either increase or decrease; it depends on its length to mass ratio.
Schematic of the Earth–Moon system (without a consistent scale)
Prisms and a Spectrum
Resonance transfer of energy in a light-harvesting complex
Precession: Earth’s axis rotates, or “wobbles”
Earth’s Spheres
Earth’s Layered Structure