Answer:
A black hole is a region of space having a gravitational field so intense that no matter or radiation can escape.
Explanation:
Sorry if this isn't what you meant or were looking for.
D. Light from the sun is reflected off the moon's surface
Answer:
ice forming and then melting back into water
Answer:

Explanation:
The work function of the metal corresponds to the minimum energy needed to extract a photoelectron from the metal. In this case, it is:

So, the energy of the incoming photon hitting on the metal must be at least equal to this value.
The energy of a photon is given by

where
h is the Planck's constant
c is the speed of light
is the wavelength of the photon
Using
and solving for
, we find the maximum wavelength of the radiation that will eject electrons from the metal:

And since
1 angstrom = 
The wavelength in angstroms is

Answer:
C
Explanation:
Velocity is just speed with direction