If two light waves are coherent, which of the following is NOT ...

[renzo156]

If two light waves are coherent, which of the following is NOT necessary?
 
  A) They must have the same frequency.
  B) They must have the same wavelength.
  C) They must have the same amplitude.
  D) They must have the same velocity.
  E) They must have a constant phase difference at every point in space.

Question 2

A simple pendulum consists of a 0.25-kg spherical mass attached to a massless string. When the mass is displaced slightly from its equilibrium position and released, the pendulum swings back and forth with a frequency of 2. Hz.
 
  What frequency would have resulted if a 0.50 kg mass (same diameter sphere) had been attached to the string instead? A) 1.41 Hz
  B) 2 Hz
  C) 2. Hz
  D) 1. Hz
  E) 4. Hz

[jaaaaaaa]

Answer to Question 1

C

Answer to Question 2

C

[renzo156]

Great answer, keep it coming

[dreamfighter72]

Gracias!