Alpha Decay

Q.

In an alpha decay, the atomic number of an element decreases by __.

Q.

On bombardment of a neutron with Boron, $\alpha$ -particle is emitted and product nuclei formed is:

1. ${}_6{C}^{12}$
   
   
   

2. ${}_{4}B{e}^9$

3. ${}_{3}L{i}^6$
   

4. ${}_{3}L{i}^7$
   

Q.

Which of the following emissions change the atomic number and mass number?

1. Gamma-emission

2. Beta-emission

3. Electron - emission

4. Alpha - emission

Q.

The element Lawrencium ${(}_{103}^{256}Lr)$ is named after Ernest Lawrence, whose invention - the cyclotron - helped discover many radioactive nuclei. Consider now, the alpha decay of ${}_{103}^{256}Lr$:
${}_{103}^{256}Lr{\to }_b^{a}Md+\alpha ,$
Where $\alpha$ represents the alpha particle given out. What are the values of a and b?

1. a=252; b=101
2. a=252; b=105
3. a=260; b=101
4. a=260; b=105

Q.

A radioactive element ${}_Z^{A}X$ loses two successive $\beta -particles$ and an $\alpha -particles$ such that resulting element is ${}_Q^{P}Y$. Find the values of P and Q in terms of A and Z.

1. ${}_{Z-2}^{A-4}Y$

2. ${}_{Z-2}^{A}Y$

3. ${}_{Z+2}^{A-4}Y$

4. ${}_Z^{A-4}Y$

Q.

The kinetic energy after an alpha decay is mainly carried by the alpha particle.

1. True

2. False

Q. What will be the daughter nuclei after 4 alpha decays of ${}_{91}^{231}Pa$

1. 
2. 
3. 
4. 

Q.

The element Lawrencium ${(}_{103}^{256}Lr)$ is named after Ernest Lawrence, whose invention - the cyclotron - helped discover many radioactive nuclei. Consider now, the alpha decay of ${}_{103}^{256}Lr$ as:
${}_{103}^{256}Lr{\to }_b^{a}Md+\alpha ,$
Where $\alpha$ represents the alpha particle given out. What are the values of a and b?

1. a=252; b=105
2. a=252; b=101
3. a=260; b=105
4. a=260; b=101

Q.

What will be the daughter nuclei after 4 alpha decays of ${}_{91}^{231}Pa$?

1. 
2. 
3. 
4. 

Q.

So, in the radioactive decay - ${}^{238}Pu{\to }^{234}U+\alpha ,$
What will be the kinetic energy of the outgoing α-particle?
Things you will need:

• Atomic masses: $m{(}^{238}Pu)=238.04955u;m{(}^{234}U)=234.04095u;m{(}^{4}He)=4.002603u.$
• Constant: $c^2=931\frac{MeV}{u}.$

1. 5.58 MeV
2. 4.72 MeV
3. 5.03 MeV
4. 3.34 MeV

Q.

An imaginary radioactive element decays to form elements $X_1,X_2,X_3,X_4,X_{5}and{X}_6$, by ejecting two $\beta$-particles, followed by an $\alpha$-particle, and again two ($\beta$-particles followed by an $\alpha$ -particle. What are the mass number and the atomic number of $X_6$?

Q.

In an alpha decay, the mass number of an element decreases by ___

Q. A nucleus with mass number A=220 decays by a-emission. the energy released is 5.5 MeV, a god estimate for the kinetic energy of the a-particle will be-

1. 4.4 MeV
2. 5.4 MeV
3. ​5.6 MeV
4. 6.5 MeV

Q.

In the radioactive decay - ${}^{238}Pu{\to }^{234}U+\alpha$,
What will be the kinetic energy of the outgoing α-particle?
Given:-

-Atomic masses:

$m{(}^{238}Pu)=238.04955u;m{(}^{234}U)=234.04095u;$

$m{(}^{4}He)=4.002603u$

-Constant: $c^2=931\frac{MeV}{u}$

1. 5.58 MeV
2. 4.72 MeV
3. 5.03 MeV
4. 3.34 MeV

Q.

Which of the following elements has same number of protons, electrons and neutrons ?

1. ${}_{13}{}^{27}\mathrm{Al}$

2. ${}_{12}{}^{24}\mathrm{Mg}$

3. ${}_{17}{}^{35}\mathrm{Cl}$

4. ${}_{11}{}^{23}\mathrm{Na}$

Q.

Which of these is at a higher energy level in an alpha decay?

1. Parent nucleus

2. Daughter nucleus and alpha particle

3. Both are equal

4. Depends on the particular case

Q. .(a)The number of nuclei of a given radioactive nucleus at time t=0 and t=T are N₀and N_O/n respectively. Obtain an expression for half life of this nucleus in terms of n and T.
(b) Identify the nature of radioactive radiations emitted in each step of the decay chain given below.
_ZX^A ------> _Z-2Y^A-4-------> _Z-2Y^A-4---------->_Z-1 W ^A-4

Q.

Which of these is at a higher energy level in an alpha decay?

1. Parent nucleus

2. Both are equal

3. Daughter nucleus and alpha particle

4. Depends on the particular case