Tag: gamma decay

Questions Related to gamma decay

A free nucleus of mass $24$ u emits a gamma photon [when initially at rest]. The energy of the photon is $7$ MeV. The recoil energy of the nucleus in keV is 

physics nuclei gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

  1. $1.1$

  2. $1.2$

  3. $1.0$

  4. $1.3$

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Correct Option: A

Hydrogen atom will be in its ground state,if its electron is in

physics nuclei gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

  1. any energy level

  2. the lowest energy state

  3. the highest energy state

  4. the intermediate state

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Correct Option: B
Explanation:

Hydrogen atom has one electron. Depending upon the electron residing in which energy state hydrogen energy varies. So, for hydrogen atom to be in ground state electron should be in lowest energy state.

When writing electron configurations,electrons are represented in their lowest possible energy state.Which of the following state is this ?

physics nuclei gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

  1. excited state.

  2. lowest state.

  3. configuration state.

  4. ground state.

  5. unenergetic state.

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Correct Option: D
Explanation:

According to Aufbau's principle, electrons are filled in the atomic orbitals in order of lower energy to the higher energy starting from the orbital of lowest possible energy known as the ground state.

A beam of ultraviolet radiation having wavelength between $100nm$ and $200nm$ is incident on a sample of atomic hydrogen gas. Assuming that the atoms are in ground state, which wavelengths will have low intensity in the transmitted beam? 

physics nuclei gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

  1. $104nm$

  2. $103nm$

  3. $105nm$

  4. $100nm$

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Correct Option: B
Explanation:

Energy corresponding to wavelength 100nm, $\dfrac{1242eV}{100}=12.42 eV$

Energy corresponding to wavelength 200nm, $\dfrac{1242eV}{200}=6.21 eV$
Energy required from ground state to first excited stage:
$E _2-E _1=13.6-3.4=10.2 eV$
Energy required from ground state to second excited stage:
$E _3-E _1=13.6-13.6-1.5=12.1  eV$

Energy required from ground state to third excited stage:
$E _3-E _1=13.6-0.85=12.75  eV$

At 10.2 eV,
$Wavelength 1=\dfrac{1242}{10.2}=122nm$

At 12.1 eV,
$Wavelength 2=\dfrac{1242}{12.1}=103nm$



The ground state energy of the electron in hydrogen atom is equal to :

physics nuclei gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

  1. the ground state energy of the electron in $ { He }^{ + } $

  2. the first excited state energy of the electron in $ { He }^{ + } $

  3. the first excited state energy of the electron in $ { Li }^{ +2 } $

  4. the ground state energy of the electron in $ { Be }^{ +3 } $

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Correct Option: B

The total energy of an electron in the ground state of hydrogen atom is $-13.6\space eV$. The potential energy of an electron in the ground state of $Li^{2+}$ ion will be

physics nuclei gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

  1. $122.4\space eV$

  2. $-122.4\space eV$

  3. $244.8\space eV$

  4. $-244.8\space eV$

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Correct Option: D
Explanation:

Therefore, for ${ Li }^{ 2+ }$ ion, Total energy is $- 13.6\times 9 = 122.4\ eV$
But, $-K.E= T.E= \dfrac { P.E }{ 2 } $
Therefore, $P.E$ is $-244.8\ eV$

The ground state energy of Hydrogen atom is $–13.6eV$. The potential energy of the electron in this state is:

physics nuclei gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

  1. $0eV$

  2. $-27.2eV$

  3. $1eV$

  4. $2eV$

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Correct Option: B
Explanation:

The ground state energy of hydrogen atom $=13.6eV$

Potential energy $=2$ energy of electron
                             $=2(-13.6\ eV)$
                             $=-27.2\ eV$

In which of the following systems will the radius of the first orbit (n = 1) be minimum ?

physics nuclei gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

  1. hydrogen atom

  2. deuterium atom

  3. singly ionized helium

  4. doubly ionized lithium.

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Correct Option: D
Explanation:

Radius of the first orbit of an atom  $R _1 = \dfrac{0.529}{Z}$  $A^o$
$\implies \ R _1 \propto\dfrac{1}{Z}$
where $Z$ is the atomic number of Hydrogen-like atom.
Since $Z$ is maximum for doubly ionized lithium, thus radius of first orbit is minimum in doubly ionized lithium.

What is energy released in the $\beta  - decay\;of{\;^{32}}P{ \to ^{32}}S?$(Given:atomic masses:31.97391 u for $\left( {^{32}P\;and\;31.97207\;u\;fo{r^{32}}S} \right)$

gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

  1. -1.2 MeV

    • 1.7 MeV

  3. +2.1 MeV

  4. -0.9 Mev

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Correct Option: B
Explanation:

Released energy will be corresponding the $mass $ $defect$ $\text{which is difference in mass of parent nuclei and daughter nuclei}$

so mass defect is $31.97391u- 31.97207 u=0.00184u=0.00184\times 931Mev=1.7Mev$ 
as $1u=931MeV $ of $ energy$.
Option B is correct.

A sample originally contained $10 ^ { 20 }$radioactive atoms, which emit $\alpha$ -particles emitted inthe thirdyear to that emitted during the second year is $0.3 $.How many $\alpha$ particles were emitted in the first year?

gamma decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

  1. $7 \times 10 ^ { 19 }$

  2. $3 \times 10 ^ { 19 }$

  3. $5 \times 10 ^ { 18 }$

  4. $3 \times 10 ^ { 18 }$

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Correct Option: A