7. How fast would a motorist have to be traveling for a yellow (A = 590 nm) traffic light to appear green (λ = 550 nm) because of the Doppler shift? Should the motorist be traveling toward or away from the traffic light to see this effect?

7. How fast would a motorist have to be traveling for a yellow (A = 590 nm) traffic light to appear green (λ = 550 nm) because of the Doppler shift? Should the motorist be traveling toward or away from the traffic light to see this effect?

Principles of Physics: A Calculus-Based Text

5th Edition

ISBN:9781133104261

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter24: Electromagnetic Waves

Section: Chapter Questions

Problem 17P: A physicist drives through a stop light. When he is pulled over, he tells the police officer that...

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The Tunguska event. On June 30, 1908, a meteor burned up and exploded in the atmosphere above the Tunguska River valley in Siberia. It knocked down trees over thousands of square kilometers and started a forest fire, but produced no crater and apparently caused no human casualties. A witness sitting on his doorstep outside the zone of falling trees recalled events in the following sequence. He saw a moving light in the sky, brighter than the Sun and descending at a low angle to the horizon. He felt his face become warm. He felt the ground shake. An invisible agent picked him up and immediately dropped him about a meter from where he had been seated. He heard a very loud protracted rumbling. Suggest an explanation for these observations and for the order in which they happened.
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 650 nm appear green to him, with a wavelength of 520 nm. The police officer writes out a traffic citation for speeding. How fast was the physicist traveling, according to his own testimony?
As a car heads down a highway traveling at a speed v away from a ground observer, which of the following statements are true about the measured speed of the light beam from the cars headlights? More than one statement may be correct, (a) The ground observer measures the light speed to be c + . (b) The driver measures the light speed to be c. (c) The ground observer measures the light speed to be c. (d) The driver measures the light speed to be c - . (e) The ground observer measures the light speed to be c - .
A Doppler weather radar station broadcasts a pulse of radio waves at frequency 2.85 GHz. From a relatively small batch of raindrops at bearing 38.6 east of north, the station receives a reflected pulse after 180 s with a frequency shifted upward by 254 Hz. From a similar batch of raindrops at bearing 39.6 east of north, the station receives a reflected pulse after the same time delay, with a frequency shifted downward by 254 Hz. These pulses have the highest and lowest frequencies the station receives, (a) Calculate the radial velocity components of both batches of raindrops. (b) Assume that these raindrops are swirling in a uniformly rotating vortex. Find the angular speed of their rotation.
An Earth satellite used in the Global Positioning System moves in a circular orbit with period 11 h 58 min. (a) Determine the radius of its orbit. (b) Determine its speed. (c) The satellite contains an oscillator producing the principal nonmilitary GPS signal. Its frequency is 1 575.42 MHz in the reference frame of the satellite. When it is received on the Earths surface, what is the fractional change in this frequency due to time dilation, as described by special relativity? (d) The gravitational blueshift of the frequency according to general relativity is a separate effect. The magnitude of that fractional change is given by ff=Ugmc2 where Ug/m is the change in gravitational potential energy per unit mass between the two points at which the signal is observed. Calculate this fractional change in frequency. (e) What is the overall fractional change in frequency? Superposed on both of these relativistic effects is a Doppler shift that is generally much larger. It can be a redshift or a blueshift, depending on the motion of a particular satellite relative to a GPS receiver (Fig. P1.39).
A train is moving at a speed of v towards the railwayman next to the rails. The train whistles for a time of T. How long does the railwayman hear the whistle? The speed of sound is c= 330 m/s; v=108 km/hour= 3) m/s, T= 3s; the train does not reach the railwayman until the end of the whistle. %3D
In the “red shift” of radiation from a distant galaxy, the light Hy, known to have a wavelength of 434 nm when observed in the laboratory, appears to have a wavelength of 462nm. What is the speed of the galaxy in the line if sight relative to Earth?
In the "red shift" of radiation from a distant galaxy, the light H, known to have a wavelength of 434 nm when observed in the laboratory, appears to have a wavelength of 462 nm. What is the speed of the galaxy in the line of sight relative to the Earth?
2. Two astronauts are 1.20 m apart in their spaceship. One speaks to the other. The conversation is transmitted to earth via electromagnetic waves. The time it takes for sound waves to travel at 346 m/s through the air between the astronauts equals the time it takes for the electromagnetic waves to travel to the earth. How far away from the earth is the spaceship? m.
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When high-energy charged particles move through a transparent medium with a speed greater than the speed of light in that medium, a shock wave, or bow wave, of light is produced. This phenomenon is called the Cerenkov effect. When a nuclear reactor is shielded by a large pool of water, Cerenkov radiation can be seen as a blue glow in the vicinity of the reactor core due to high-speed electrons moving through the water as shown. In a particular case, the Cerenkov radiation produces a wave front with an apex half-angle of 53.0°. Calculate the speed of the electrons in the water. The speed of light in water is 2.25 × 108 m/s.
(a) The distance to a star is approximately 4.97 × 10¹8 m. If this star were to burn out today, in how many years would we see it disappear? years (b) How long does it take sunlight to reach Earth? minutes (c) How long does it take for a microwave radar signal to travel from Earth to the Moon and back? (The distance from Earth to the Moon is 3.84 x 105 km.) S