What is the frequency of the yellow-orange light (wavelength λ = 589 nm) produced by sodium-vapor streetlights? (Hint: c = vλ, where v is frequency, c is the speed of light, λ is the wavelength in meters)
a. 5.09 × 10¹⁴ Hz
b. 3.22 × 10¹⁴ Hz
c. 6.42 × 10¹⁴ Hz
d. 2.54 × 10¹⁴ Hz