Tag: nuclear physics

Questions Related to nuclear physics

The number of neutrons decreases by 1 after radioactive decay. Identify the type of decay.

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

  1. Alpha decay

  2. ${\beta}^{-}$ decay

  3. ${\beta}^{+}$ decay

  4. Electron capture

  5. Gamma decay

Show answer
Correct Option: B
Explanation:

We know that for $\beta^-$ decay, one neutron is converted into proton and electron and the electron is ejected in the reaction. For this, the number of neutrons will decrease by one unit. 

But in $\beta^+$  decay , the positron is ejected and neutron number will increase by one unit. 

Compared to the parent nucleus, the daughter nucleus of a $\beta$ decay has:

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

  1. the same mass number but a smaller atomic number

  2. the same mass number but a greater atomic number

  3. a greater mass number but the same atomic number

  4. a smaller mass number but the same atomic number

  5. None of the above

Show answer
Correct Option: B
Explanation:

When beta decay occurs, the atomic number of nucleus will increase by one unit and mass number will remain same. Thus, here the after beta decay the daughter nucleus has same mass number as product nuclei and one unit atomic number will increase than parent nuclei.    

When carbon $-14$ undergoes beta (electron) decay, it transmutes into what?

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

  1. $Carbon-13$

  2. $Carbon-12$

  3. $Nitrogen-13$

  4. $Nitrogen-12$

  5. $Nitrogen-14$

Show answer
Correct Option: E
Explanation:
Beta decay of Carbon-14 : $^{14} _{6}   $ $ \rightarrow$  $^{A} _ZX $ $+$  $^{0} _{-1} e$

Conservation of mass number :  $14 = A+ 0$    $\implies A = 14$
Conservation of atomic number :  $6 = Z-1$    $\implies Z =7$
Thus the daughter nucleus is: $^{14} _{7} N$  or  $Nitrogen- 14$.

Find out the product of a $Co^{60}$ atom that undergoes one beta plus decays?

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

  1. iron-60

  2. manganese-60

  3. copper-60

  4. copper-62

  5. iron-62

Show answer
Correct Option: A
Explanation:

$\beta^+$ decay: $^{60} _{28}Co \rightarrow$ $^{A} _{Z}X$ $+$ $^0 _{+1}e$ 

In a nuclear reaction, the mass number as well as the atomic number is conserved.
$\therefore$  $60 = 0 + A$ $\implies A =60$
Also, $27 = 1 + Z$  $\implies Z = 26$
Thus, the product of the reaction is iron-60  i.e $^{60} _{26}Fe$.

In $\beta$ decay.

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

  1. Atomic number decreased by one

  2. Mass number decreases by one

  3. Proton number remains the same

  4. Neutron number decreases by one

Show answer
Correct Option: D
Explanation:

Beta decay of $ _Z^A X$ :    $ _Z^A X \rightarrow   _{Z+1}^A Y$ $+$ $  ^o _{-1}e$

Number of protons in X: $p _x = Z $
Number of neutrons in X: $n _x = A-Z$

Number of protons in Y: $ p _y= Z+1 $
Number of neutrons in X: $ n _y= A-(Z+1) =  A-Z - 1 $

$\implies$  $n _y = n _x -1$
Thus neutron number decreases by one in beta decay.

When an atom undergoes $\beta$-decay, its atomic number

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

  1. Does not change

  2. Increases by $1$

  3. Decreases by $1$

  4. Increases by $2$

Show answer
Correct Option: B
Explanation:
When an atom undergoes $\beta$-decay the atomic number increases by 1.

When an atom undergoes $\beta$-decay, one of the neutrons breaks into one proton and one electron. The resultant electron is then ejected out of the nucleus and this is called as the $\beta$ particle. While the resultant proton stays inside the nucleus which results in increase of atomic number by 1, whereas the atomic mass remains invariant.

Hence the correct answer is option B.

10 grams of $^{57}Co$ kept in an open container beta-decays with a half-life of $270$ days. The weight of the material inside the container after $540$ days will be very nearly.

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

  1. $10g$

  2. $5g$

  3. $25g$

  4. $125g$

Show answer
Correct Option: A
Explanation:

$^{57}Co$ is undergoing beta decay i.e electron is being produced.But an electron has very less mass ($9.11\times10^{-31}kg$) as compared to the $Co$ atom.therefore,after $570$ days,even the atom go under large beta decay,the weight of the material in the container will be nearly $10 g$.

During a $\beta ^-$ decay which of the following statements are correct?

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

  1. The daughter nucleus has one proton less than the parent nucleus

  2. The daughter nucleus has one proton more than the parent nucleus

  3. An electron which is already present within the nucleus is rejected

  4. A neutron in the nucleus decays emitting an electron

Show answer
Correct Option: B
Explanation:
$\beta ^- Decay$
$^\theta _{-1}e$ or $^o _{-1}\beta \rightarrow$ Symbols for Beta particles emitted during $\beta^-$ decay.
$\theta \rightarrow$ electron is emitted
Eg- $ _{ 53 }^{ 131 }{ I }\rightarrow _{ 54 }^{ 131 }{ Xe }+ _{ -1 }^{ 0 }{ \beta  }+\bar { { \upsilon  } _{ e } } $
where,  $ _{ -1 }^{ 0 }{ \beta  }$ is $\beta$ particle
$\bar { { \upsilon  } _{ e } }$ is antineutrino
So, $(B)$ is correct option.

Masses of neutron, proton and electron are $1.0087$U, $1.0073$u and $0.0005$u respectively. If a neutron decays into a proton and an electron, the energy released would be about.

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

  1. $0.68$ MeV

  2. $0.84$ MeV

  3. $0.75$ MeV

  4. $1.22$ MeV

Show answer
Correct Option: B
Explanation:

$^1 _0n\rightarrow$ $^1 _1p+$ $^0 _{-1}e$
$Q=(m _n=m _p-m _e)c^2$

$=0.0009\times 931.5$.
0.84

During $\beta-decay$ (beta minus), the emission of antineutrino particle is supported by which of the following statement(s)?

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

  1. Angular momentum conservation holds good in any nuclear reaction.

  2. Linear momentum conservation holds good in any nuclear reaction.

  3. The KE of emitted $\beta-particle$ is varying continuously to a maximum value.

  4. None of the above.

Show answer
Correct Option: A,B,C
Explanation:

The following principles hold true in any situation in the universe
1. Conservation of linear momentum (if no external force)
2. Conservation of angular momentum (no external moment)
2. Conservation of energy
3. Conservation of charge