26.4 Photons (copy) (copy)

26.4 Photons

• Scientists faced a serious dilemma in the first three decades of the 20th century.

• If we accept this model, we must have both wave-like and particle-like behaviors.
• The dual nature of pho tons was tested in a dramatic way.

• The hypothesis that has both particle and wave properties was ported by Soviet physicists.

• A double-slit setup was used by Vavilov and Brumberg.
• They wanted to make it easier to detect individual photons by reducing the number of them that pass through the slits.
• They used extreme sensitivity to low intensities of light to detect.
• A person who is sitting in a dark room for extended periods of time develops increasing visual sensitivity to the extent that he or she can eventually see the individual photons hitting a screen that has been covered with a special material.

• There is a light source with variable intensity.

• Only two bright bands should appear.

• There should be many bright and dark bands.

• There should be many bright and dark bands.

• The flashes at low intensity indicate that the photons hit the screen.

• There are places where constructive wave interference occurs.

• Both wave-like and particle-like behaviors are exhibited by the photons.

• The results of the experiment were astounding-- they only reached screen locations where the waves from the two slits would not interfere with each other.
• It is as if each individual photon passes through both slits, interfering with itself, and then producing a flash only at a location on the screen where constructive interference occurs.

• The idea of a photon as a single quantum of radiation was constructed earlier in the chapter.
• It seems impossible that it could pass through both slits at the same time.
• The experiment supports this strange idea.

• The photoelectric effect is what we have seen.
• This suggests that the photon must have something in it.
• Because they travel at light speed, they must be treated with care.

• There are difficulties when applying this expression to a photon.
• If they are quanta of electromagnetic radiation, they would seem to be composed of electric and magnetic fields.
• The nu merator should be zero.

• We need an expression that doesn't have a square root factor.

• In the second equation, 22 is added to the first equation.
• This takes a lot of math.

• There is a new equation for the total energy of an object.

• In other words.

• What happens when Eq.

• The total energy of this expression is reasonable.
• We will talk about the object at rest and the experiment later in the chapter.

• The sun is 1030 km away.

• The Sun emits over 1045 photonss.

• There is an assumption that al photons have a Frequency of 1014 Hz.
• It will be different.

• X-rays will be used to test this expression.
• We need to know about X-rays.

• The story of X-rays is an example of how persistence and attention can lead to discoveries.
• The photoelectric effect was explained by the idea that free electrons reside inside metals.

• Physicists didn't know that metals con heats cathode in the 19th century.

• There was a potential difference across the electrodes.

• There are some ways to study the photoelectric effect.
• The difference was that the bat tery's negative terminal could be heated to high temperatures, instead of being exposed to light.

• When the tube was heated, a current appeared in the circuit and it glowed.
• The tube's interior was a vac uum, so they thought that the cathode must emit some kind of rays.

• The Cavendish Laboratory at Cambridge University was where J. J. Thomson was working.
• When the rays hit the metal target, it became negatively charged.
• Thomson found that the rays could be diverted by electric and magnetic fields as though they were negatively charged particles.
• Experiments by other scientists portended the latter hypothesis.
• The charge-to-mass ratio was not dependent on the choice of material.

• Thomson concluded that there was only one type of cathode ray.

• If we can explain the behavior of the cathode ray tubes, we can model a stream of charged particles.
• The tube is hot.
• The particles inside the cathode have a large amount of random motion and could knock each other out.
• The electric field between the anode and the cathode would cause them to accelerate.

• The chemists were trying to find out what electric currents were made of.
• The value of the smal est charge carried by these particles was determined through experiments.

• The mass of the electron is less than that of a hydrogen atom.

• The electron is a point tube.
• If you put the tube in on the electron and the Earth exerts the same force on it as it does on the electric, what happens?

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• The negatively charged elec speed can be determined by determining the charge-to-mass ratio.

• The trons follow a path.

• There should be a relationship between downward.

• Experiments with tubes led to the discovery of X-rays.

• When Roentgen was ready to leave the lab, he covered the cathode ray tube with cardboard and turned off the lights.
• The room was dark and the tube was covered in cardboard.
• The lights were turned back on by Roentgen.

• The screen was not bright.

• Most people would have exhaled a sigh of relief and left.

• The tube is completely covered.
• Roentgen could see a shadow on the screen when he placed his hand near it.

• The screen glowed as though the flesh of his hand was transparent, and only his bones stopped it.

• At the time he couldn't explain what the rays were, he called them X-rays.
• The first X-ray image of a human was made by Roentgen on December 22, 1895.
• X-rays are still called X-rays even though we know what they are.

• X-rays are unaffected by magnetic or electric fields.

• The X-rays don't cause the screen to charge.

• The photographic paper is affected by X-rays.

• After a single narrow slit, the X-rays produce a pattern of dark and bright bands on the screen.

• X-rays can be different colors.

• There are many materials that can be X-rayed.

• X-rays can be used to ionize gases.

• The X-rays had a wavelength of 10 to 11 m, which was much smaller than visible light.
• It is reasonable to think that X-rays are streams of high energy photons.

• The metal is very hot due to their high random motion.

• The electrons are hot when they escape the cathode.

• When an electron stops when it collides with the anode, it emits electromagnetic radiation.
• The radiation may be in the form of electron is ejected.

• The X-rays are emitted when there is an X-ray photon.
• The amount of energy produced by the electrons is estimated.

• We want to know if the electrons are enough to produce an X-ray photon.

• The potential difference between the electric field produced in a hospital and the one produced by a single X-ray tube is considered.
• Each part of the process is represented by electrons that stop abruptly a work-energy bar chart.
• The initial state shown below is when they collide with the anode and emit light.

• The process is sketched in three zero electric potential energy.

• The electron smashes into the anode.
• The X-ray photon has been emitted.

• The energy characteristic of vis ible light is less than this.

• The generalized work-energy principle is higher than visible light frequencies and can be applied using the first and second state.

• The constant is 10-34 J #s.

• The result of our calculation shows that an elec tron can produce an X-ray photon when it stops.

• Each photon must have a specific amount of momentum.
• We thought LF moved away at angle U.

• We need to describe the process.

• The stationary electron has zero initial momentum.

• The energy of the system should be constant.
• The system has no electric potential energy because the pho ton is neutral.
• The internal energy of the sys tem is zero because the photon and electron have no internal structure.
• We need to keep track of the energy of the electron and the photon.

• The equation can be combined with the two equa tions into a single relationship that describes the collision between the X-ray photon and the electron.
• It is complicated because of the high speeds involved.

• The wavelength of an X-ray photon after the col ision should always be greater than or equal to the wavelength before the collision if the hypothesis about X-rays behaving like particles is correct.
• The right side of the book is the reason.
• The magnitude of the photon's momentum can change.
• The finding is reasonable because of the transfer of the photon's momentum to the electron.

• Arthur Compton conducted an experiment in 1922 to find out if the photon's wavelength actually changes.
• He shot a beam of X rays.
• The binding energy between the electrons and the carbon atoms is 1000 times greater than the X-ray photons.
• The electrons can be approximated as isolated and not interacting with the carbon atoms.

• The photons had different wavelength than the incident.
• The change in the photon wavelength as a function of its scattering angle was consistent.
• With greater confidence, we can assert this idea.

• The ideas about scattering from charged particles can now be summarized.

• The effect that carries his name was described by the winner of the 1927 Nobel Prize.

• Each photon has enough energy to knock electrons out of atoms or to break bonds that hold atoms together in molecule, so they are cal ed ionizing radiation.
• Ionizing radiation can damage genes and increase the risk of cancer.
• The chance of serious harm from UV and X-ray exposure is reduced by the body's potent DNA repair mechanisms.
• People who work around ionizing radiation have to take precautions.

• If the body absorbs a total of 1 then the chest X-ray will be 10-3 J.

• Three times as long the number of photons will be.

• Cosmic rays coming from supernovae and other objects in the universe can be seen in the food you eat.
• You absorb about 10-3 J of this radiation per kilogram of body mass.
• Estimate the number of seconds that the ionizing and the strontium-90 particles are absorbed each second.

• Assume for nisms to take care of radiation exposure.

• We can determine the number absorbed each time we are exposed to radiation.

• The X-ray photons have particle-like behavior.
• X-rays can exhibit wave-like behavior if they can be made to interact with objects that are similar to the wavelength of the X-rays.
• The order of magnitude is the same as the wavelength of X-ray photons.
• The pattern of visible light and/or UV radiation is very similar to that of the crystal lattice.
• The electrons move to the collector.

• The structure of genes can be determined using X-ray scat tering.

• A key role in determining the structure of DNA was played by British biophysicist Rosalind Franklin.

• The electrons go from the emitter to the collector in photocells and solar cells.

• There are many applications of the photoelectric effect.

• An electric current detector is caused by a photoelectric smoke electrons being ejected and absorbed by the col ector.

• The magnitude of the current is a measure of the visible light.

• Solar cells, such as the rooftop panels used to generate electric current, are triggered when the pho tocurrent reaches a certain level.

• The No smoke Semiconductor technology we discussed in the earlier chapter is used to make solar cells.

• Semiconductors act as conductors under some conditions.

• Silicon is used in electronics.

• Each electron is shared between them.
• A light reaching electrons is an electric insulator.
• When the photocell light shines on it, some of the electrons gain enough strength to make an alarm sound.

• Smoke holes can be filled by other bound electrons that aren't as energetic as Smoke scatters light can still move among the still-bound elec trons.
• If the Silicon is placed in an electric field, both free electrons and holes can potentially contribute to a current.

• The alarm process uses light and Scattered light to increase the energy of the Silicon and allow some of it's electrons to be free.
• The be freed depends on the light's frequencies.

• Enhancing the purity of Silicon is one way to turn it into a conductor.
• The two types of impurities are electron donors and electron acceptors.

• Doping of a substance.

• Charge transfer across the junction is not caused by light p- and n-type Semiconductors.

• A free electron is produced.

• For an electron acceptor, the opposite is true.
• Boron has holes because it absorbs the Sun's three electrons.
• Extra holes can be created by the separation of the electric field bond with the adjacent Silicon atoms.

• The holes act as free positively charged particles without the presence of light.

• The crystals are completely composed of neutral atoms.

• An electric field is produced by this charge separation.

• If we shine light on the p-n junction, both halves cause a hole to move left and the junction will absorb energy from the left side.

• The freed electrons and holes are separated by an electric field created by the p-n junction.
• If we connect a lightbulb to the two ends of the p-n junction, we will see a current in the circuit and the bulb will light.
• The energy of light is converted into electricity.

• The electron has zero energy when it leaves the metal if the photon energy is greater than f.

• The maximum speed electron can't reach the anode.

• If you triple the temperature of a black body, the 10.

• The wavelength frequency is the temperature of a black body.

• You can choose al of the photoelectric 11.

How do we know that there is a particle-like model of light?

• The intensity of light is proportional to the photon model of light.

• The photon model of light and rent are different.

• The Sun emits X-rays.
• The intensity of light is what determines why we are.

• The photoelectric effect and the Comp 7 are very different.

• The photoelectric effect has a photon with momentum.

• The work function of cesium is 2.1 eV.
• Someone could be sium.

• Determine how much diation is emitted by each surface.

• A blue tion could be a solution to the problem of where the most energy comes from.

• The stars range in color from red to blue.
• In an old-fashioned camera, the film color indicates the frequencies at which the star is exposed when light strikes it, estimating chemical reaction.
• The surface temperature of red, yel ow, white, and blue stars is not caused by a particular type of film.

• The lightbulb's surface area should be estimated.

• The surface temperature of the filament when it is plugged into an outlet of 120 V is 3000 K and the power 18.
• The electric energy/s that the bulb consumes is the electric energy/s that the carbon monoxide molecule rating of the bulb produces.
• Incandescent lightbulbs use about 10% of the electric energy that they consume, so they use the same visible Frequency of CO vibration as the Frequency light.

• Suppose the bond in a molecule is broken by a single photon from 1.0 cm2 of energy.
• Determine the fre person's skin if a typical emitted photon has a wavelength of quiescent and a region of 10,000 nm.

• The photon's wavelength is 1240 nm.
• The ratio tech compares the average power of the surface of Earth to determine the wavelength of a photon.

• Exposure to the entire surface of a warm object in a tanning bed.
• It can do a lot of damage if wavelength 300 nm is used.
• The average temperature of Earth's surface is 15 C.

• Determine the number of 650-nm photons that have the same amount of energy as an electron.

• Draw a picture of a phototube and electric circuit body tissues.
• To study the photoelectric effect, you have to build a number.
• If you want to understand the purpose of each part, you need to label all of the 10.8@mm photons and the average power dur of the pulse parts.

• Write a problem for which the equa is 20 times per second for the unknown quantity in wavelength pulse of variable energy.
• It is possible to determine the number of photons in tion.

• About 1400 W>m2 is the intensity of light reaching Earth.
• Determine the number of particles.
• Each second, an incident reaches a 1.0@m2 area.

• Determine the energy in 28.
• Roughly 10% of the power of a 100 watt in crease of the electron, in units of electron volts, when the pho candescent lightbulb is emitted as light, is scattered from it.

• An electron hit by an X-ray photon of energy is equal to 104 eV.
• If the photon leaves the site of the collision, how will the answer change?

• To see a 0.20 J object.
• The light wavelength is 694.
• The minimum light pulse to be determined.

• A powerful laser can ond in order to see an object.
• The wavelength of the light and the lift and support glass spheres that are 20.0 * 10 m in diam radius are assumed.

• Ex eye can detect one photon of light of wavelength and how they work together to produce cathode rays.

• Each 31 would be the number of such photons that enter the eye.

• They are very efficient at converting.

• 33 are most living organisms.
• The fireflies use adenosine triphosphate as an energy mol ence.
• A firefly would crash into the X-ray tube if it was given a number of ATP molecules.

• The laser is moving toward the center of the screen.
• The light shines on the sail of a tiny 0.10-g cart that expression for the strength of the field so the electron hits the can coast on a horizontal frictionless track.

• The light is total.

• The light is a total field.
• The absorbed by the sail must be determined.

• There are comets.
• A person absorbs jects that move around the Sun while being X-rayed.
• The number of comet's head is determined by the amount of X-ray photons absorbed during the exam.

• When the comet is close to the sun, there are gases and dust.
• Independent absorbs X-ray radiation.
• The tail always points to a positive charged ion in the direction of the comet.

• Roughly 150 million km from Earth is the Sun.

• The original experiment involved scattering.

• Canis Major is the second-brightest star in the north ton when it collides with an electron or with a carbon ern sky.
• Its surface temperature is an atom and it travels at a 90 angle.

• The minimum number of plants that capture and store energy from the Sun should be estimated.
• Use the assumptions you used in mak to build complex molecules.
• The process begins.

• The reverse reaction releases a lot of energy.

• Determine the ratio of the energy released from one antenna to another until it reaches an "acceptor" molecule.
• The energy absorbed by the acceptor is passed to an electron transport chain, where it is captured and stored.

• The electron transport chain, dium surface with a work function of 2.2 eV, is made of waves.

• The light is reflected from a mirror.
• Determine the force that the light exerts on the mirror.

• Suppose one of the antenna molecules absorbs a photon.

• 1400 J>s # m2 is the photon and tion intensity of a molecule like this.
• The original energy state can be determined in about 10-8 s.

• The radiation on Earth is linked to the antenna molecule in the photosynthetic units.

• A photon is absorbed by one antenna.
• If we wanted to support molecule, we could levitate the person on a beam of light.

• The person's neighbors are more or less random.

• An electron is located in an open region of space port chain.
• The energy is struck by a photon of light at several places along this pathway.

• The photographs were taken with a regular camera and an infra.

What is the number of antenna molecules that can be absorbed by a black plastic bag?

• The photoelectric transfer of an electron to the electron transport chain can be accomplished if the neighboring antenna molecules are separated by 10 m.

• The antenna molecule that absorbed the photon is the source of the high-energy electron that transfers into an electron trans port chain.

• The man's glasses appear clear with the regular camera photo, which comes from the acceptor molecule that is excited by and black with the IR camera photo.

• A person's body can't be that way.

• The law gives the peak wavelength of the radia face.

• A and b and c radiation are included.