For the Doppler effect to occur, there must be a. a moving ...

[Ebrown]

For the Doppler effect to occur, there must be
 a. a moving source.
  b. a moving observer.
  c. relative motion between a source and an observer.
  d. no motion.

Question 2

The energy needed to change a He+ ion in the ground state into a He2+ ion is
 a. 13.6 eV
  b. 54.4 eV
  c. 112.4 eV
  d. 92.9 eV
  e. 27.2 eV

[at]

Answer to Question 1

c

Answer to Question 2

b

[Ebrown]

Thanks for the timely response, appreciate it

[aliotak]

Excellent