Answer
given,
wavelength of the red light,λ = 687 nm
wavelength of the yellow light = 582 nm
Frequency of red light
=
=
= 4.36 x 10¹⁴ Hz
frequency of the yellow light
=
= 5.15 x 10¹⁴ Hz
speed of the car
v_r is the required speed.
v_r = 0.19 c
v_r = 0.19 x 3 x 10⁸ =5.7 x 10⁷ m/s
1 m/s = 2.23694 mile/hr
v_r = 1.27 x 10⁸ mile/hr
if the light is actually yellow
f₀ = 5.15 x 10¹⁴ Hz
f = 6.13 x 10¹⁴ Hz
wavelength corresponding to this frequency is wavelength = 493.2 nm
hence, the color corresponding to this wavelength is Green.