A physicist drives through a stop light. When he is pulled over, he tells the police officer that the Doppler shift made the red light of wavelength 680 nm appear green to him, with a wavelength of 515 nm. The police officer writes out a traffic citation for speeding. How fast was the physicist traveling, according to his own testimony?

The speed is

Explanation:

From the question we are told that

   The real  wavelength is  

   The observed  wavelength is

Generally the real wavelength of the stop light according to doppler effect is mathematically as

Here c is the speed of the light  

and  v is the speed of the physicist

So

=>    

=>    

=>  

=>  

=>  

=>  

=>  

substituting  for c

    =>    

    =>    

  distance on the y-axis and time on the x-axis.

explanation:

the instantaneous velocity = change in position/time taken

the slope of the graph should give instantaneous velocity.

  slope of a graph = change in value of y -axis / change in values of x -axis

  comparing both the equations

    change in value of y -axis = change in position

  change in values of x -axis = time taken

so position values should be on the y axis and time values should be on the x axis.

distance on the y-axis and time on the x-axis.