Light having a frequency in vacuum of 6.0 × 10^14 Hz enters a liquid of refractive index 2.0. What is the frequency of the light in this liquid? (c = 3.0 × 10^8 m/s)
a. 1.0 × 1014 Hz
b. 3.0 × 1014 Hz
c. 6.0 × 1014 Hz
d. 12.0 × 1014 Hz