/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 22 (I) The \(^{7}_{3}\)Li nucleus h... [FREE SOLUTION] | 91Ó°ÊÓ

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(I) The \(^{7}_{3}\)Li nucleus has an excited state 0.48 MeV above the ground state. What wavelength gamma photon is emitted when the nucleus decays from the excited state to the ground state?

Short Answer

Expert verified
The wavelength of the emitted gamma photon is approximately \(2.586 \times 10^{-12}\) meters.

Step by step solution

01

Understand Energy Transition

The task is to find the wavelength of a gamma photon emitted when the nucleus transitions from an excited state to the ground state. The energy difference between these states is given as 0.48 MeV, which is the energy of the emitted photon.
02

Convert Energy from MeV to Joules

Energy is often given in mega-electron volts (MeV) in nuclear physics, but to find the wavelength, we need it in joules. Use the conversion 1 MeV = \(1.60218 \times 10^{-13}\) Joules. Therefore, 0.48 MeV is equal to \(0.48 \times 1.60218 \times 10^{-13} = 7.69046 \times 10^{-14}\) Joules.
03

Use the Energy-Wavelength Relationship

The energy of a photon is related to its wavelength by the equation \(E = \frac{hc}{\lambda}\), where \(E\) is the energy in joules, \(h\) is Planck's constant \(6.626 \times 10^{-34} \text{ Js}\), \(c\) is the speed of light \(3.00 \times 10^{8} \text{ m/s}\), and \(\lambda\) is the wavelength in meters.
04

Solve for Wavelength \(\lambda\)

Rearrange the equation \(E = \frac{hc}{\lambda}\) to solve for \(\lambda\): \(\lambda = \frac{hc}{E}\). Substitute \(h = 6.626 \times 10^{-34}\) Js, \(c = 3.00 \times 10^{8}\) m/s, and \(E = 7.69046 \times 10^{-14}\) J into the formula: \(\lambda = \frac{6.626 \times 10^{-34} \times 3.00 \times 10^{8}}{7.69046 \times 10^{-14}}\).
05

Calculate the Wavelength

Perform the calculation: \(\lambda = \frac{6.626 \times 10^{-34} \times 3.00 \times 10^{8}}{7.69046 \times 10^{-14}}\). This calculation gives \(\lambda \approx 2.586 \times 10^{-12}\) meters.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Energy Transition
When a nucleus undergoes a transition from an excited state to its ground state, it releases energy in the form of electromagnetic radiation. This process is known as an energy transition. In this context, the energy difference is released as a gamma photon. Gamma photons are highly energetic and are often emitted in nuclear reactions.

The energy of the emitted photon corresponds to the energy difference between the two nuclear states. In our example, this energy is equal to 0.48 MeV. Understanding energy transitions is crucial as they help us determine how much energy is released and what kind of photon is emitted.
MeV to Joules Conversion
In nuclear physics, energy is often measured in mega-electron volts (MeV). However, many calculations require energy to be in joules, a more universal unit. Thus, converting MeV to joules is necessary.

The conversion factor is simple:
  • 1 MeV = \( 1.60218 \times 10^{-13} \) joules.
To convert, you simply multiply the energy in MeV by this factor. For example, an energy of 0.48 MeV can be converted to joules by multiplying:
  • 0.48 MeV \( \times 1.60218 \times 10^{-13} \) joules = \( 7.69046 \times 10^{-14} \) joules.
This conversion allows us to use the energy value in further physics calculations, especially when associating energy with wavelength.
Planck's Constant
Planck's constant is a fundamental constant in physics, denoted by \( h \). It is critical in the study of quantum mechanics and relates the energy of a photon to its frequency. The value of Planck's constant is approximately \( 6.626 \times 10^{-34} \text{ Js} \).

Planck's constant is essential in deriving the photon energy equation. It enables calculations involving the quantum nature of particles, bridging energy, and wave characteristics. In our exercise, it is used to find the relationship between the energy of a gamma photon and its wavelength. Understanding Planck's constant is vital because it underpins how physical quantities like energy and wavelength interconnect at a quantum level.
Photon Energy Equation
The photon energy equation expresses the relationship between a photon's energy and its wavelength and involves several constants including Planck's constant \( h \) and the speed of light \( c \). The equation is given by:
  • \( E = \frac{hc}{\lambda} \)
Where:
  • \( E \) is the energy of the photon in joules,
  • \( \lambda \) is the wavelength in meters,
  • \( h \) is Planck's constant \( 6.626 \times 10^{-34} \text{ Js} \),
  • \( c \) is the speed of light \( 3.00 \times 10^{8} \text{ m/s} \).
This equation allows us to calculate the wavelength of a photon given its energy, or vice versa. In our exercise, rearranging this equation to \( \lambda = \frac{hc}{E} \) lets us find the wavelength of a gamma ray emitted during an energy transition. Understanding and using this equation is fundamental in analyzing the behavior of photons in various physical contexts.

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Most popular questions from this chapter

(III) (a) Show that the nucleus \(^{8}_{4}\)Be (mass \(=\) 8.005305 u) is unstable and will decay into two \(\alpha\) particles. (\(b\)) Is \(^{12}_{6}\)C stable against decay into three \(\alpha\) particles? Show why or why not.

Some elementary particle theories (Section 32-11) suggest that the proton may be unstable, with a half-life \(\geq\) 10\(^{33}\) yr. (\(a\)) How long would you expect to wait for one proton in your body to decay (approximate your body as all water)? (\(b\)) Of the roughly 7 billion people on Earth, about how many would have a proton in their body decay in a 70 yr lifetime?

\(\textbf{Tritium dating}\). The \(^{3}_{1}\)H isotope of hydrogen, which is called \(tritium\) (because it contains three nucleons), has a half-life of 12.3 yr. It can be used to measure the age of objects up to about 100 yr. It is produced in the upper atmosphere by cosmic rays and brought to Earth by rain. As an application, determine approximately the age of a bottle of wine whose \(^{3}_{1}\)H radiation is about \(\frac{1}{10}\) that present in new wine.

(II) A photon with a wavelength of 1.15 \(\times\) 10\(^{-13}\) m is ejected from an atom. Calculate its energy and explain why it is a \(\gamma\) ray from the nucleus or a photon from the atom.

(II) Two of the naturally occurring radioactive decay sequences start with \(^{232}_{90}\)Th and with \(^{235}_{92}\)U. The first five decays of these two sequences are: $$\alpha, \, \beta, \, \beta, \, \alpha, \, \alpha, $$ and $$\alpha, \, \beta, \, \alpha, \, \beta, \, \alpha.$$ Determine the resulting intermediate daughter nuclei in each case.

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