The apparent motion of an object when it is viewed from two different positions against a fixed background is called
a. Hubble's effect.
b. parallax.
c. paradox.
d. Brighton's effect.
Question 2
When an electron in an atom falls from a higher energy level to a lower one, a ______________ is ______________.
a. proton; absorbed
b. proton; emitted
c. photon; absorbed
d. photon; emitted