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Ch 38: Photons: Light Waves Behaving as Particles
Young & Freedman Calc - University Physics 14th Edition
Young & Freedman Calc14th EditionUniversity PhysicsISBN: 9780321973610Not the one you use?Change textbook
Chapter 38, Problem 21

X rays with an initial wavelength of 0.900×10100.900\(\times\)10^{-10} m undergo Compton scattering. For what scattering angle is the wavelength of the scattered x rays greater by 1.0%1.0\% than that of the incident x rays?

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Determine the relationship between the change in wavelength (Δλ) and the scattering angle (θ) using the Compton wavelength shift formula: Δλ = (h / (m_e * c)) * (1 - cos(θ)), where h is Planck's constant, m_e is the electron mass, and c is the speed of light.
Calculate the change in wavelength (Δλ) as 1.0% of the initial wavelength: Δλ = 0.01 * 0.900 × 10^-10 m.
Substitute the known values of Δλ, h, m_e, and c into the Compton formula to isolate the term (1 - cos(θ)): (1 - cos(θ)) = Δλ / (h / (m_e * c)).
Solve for cos(θ) using the equation: cos(θ) = 1 - (Δλ / (h / (m_e * c))).
Finally, calculate the scattering angle θ by taking the inverse cosine (arccos) of the result: θ = arccos(cos(θ)).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Compton Scattering

Compton scattering is a phenomenon where X-rays or gamma rays collide with matter, resulting in a change in the wavelength of the radiation. This effect occurs due to the interaction between photons and electrons, leading to the transfer of energy and momentum. The change in wavelength is dependent on the scattering angle, which can be calculated using the Compton wavelength shift equation.
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Wavelength Shift

The wavelength shift in Compton scattering refers to the difference in wavelength between the incident and scattered X-rays. It can be quantified using the formula Δλ = λ' - λ = (h/m_ec)(1 - cos(θ)), where h is Planck's constant, m_e is the electron mass, c is the speed of light, and θ is the scattering angle. A 1% increase in wavelength indicates a specific relationship between the initial and final wavelengths that must be calculated.
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Scattering Angle

The scattering angle is the angle at which a photon is deflected after colliding with an electron. It plays a crucial role in determining the change in wavelength during Compton scattering. By analyzing the relationship between the scattering angle and the resulting wavelength shift, one can derive the angle that corresponds to a specific increase in wavelength, such as the 1% increase mentioned in the question.
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Related Practice
Textbook Question

A photon scatters in the backward direction (ϕ=180\(\phi\)=180°) from a free proton that is initially at rest. What must the wavelength of the incident photon be if it is to undergo a 10.0%10.0\% change in wavelength as a result of the scattering?

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Textbook Question

A horizontal beam of laser light of wavelength 585585 nm passes through a narrow slit that has width 0.06200.0620 mm. The intensity of the light is measured on a vertical screen that is 2.002.00 m from the slit.

(a) What is the minimum uncertainty in the vertical component of the momentum of each photon in the beam after the photon has passed through the slit?

(b) Use the result of part (a) to estimate the width of the central diffraction maximum that is observed on the screen.

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An electron and a positron are moving toward each other and each has speed 0.500c0.500c in the lab frame. What is the kinetic energy of each particle?

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An ultrashort pulse has a duration of 9.009.00 fs and produces light at a wavelength of 556556 nm. What are the momentum and momentum uncertainty of a single photon in the pulse?

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The cathode-ray tubes that generated the picture in early color televisions were sources of x rays. If the acceleration voltage in a television tube is 15.015.0 kV, what are the shortest-wavelength x rays produced by the television?

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