Question

Imagine that a motorist is travelling so fast that the yellow light (585 nm wavelength) from a traffic signal appears green (555 nm wavelength). Find the velocity of the motorist, assuming the positive direction is defined as moving closer to the light.

Question 8 options:

A) 

1.64 x 10⁷ m/s

B) 

2.64 x 10⁷ m/s

C) 

3.64 x 10⁷ m/s

D) 

No option is correct

E) 

4.64 x 10⁷ m/s

Answer 1

Velocity of the motorist:

$$v=c\bigg(\frac{\lambda_0}{\lambda}-1\bigg)=1.62·10^7\text{ m/s}.$$