Q. No.Given below are two statements:
| Assertion (A): | In \(\alpha \text-\text{decay}\) atomic number of the daughter nucleus is reduced by \(2\) units from the parent nucleus. |
| Reason (R): | An \(\alpha \text-\text{particle}\) carries four units of mass. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
Subtopic: Â Types of Decay |
 80%
From NCERT
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An excited heavy nucleus \(^A_Z \mathrm{X}\) emits radiations in the following sequence:
\(^A_Z \mathrm{X}\rightarrow ^{A-4}_{Z-2}\mathrm{D_1}\rightarrow ^{A-4}_{Z-1}\mathrm{D_2}\rightarrow ^{A-8}_{Z-3}\mathrm{D_3}\rightarrow ^{A-8}_{Z-4}\mathrm{D_4}\rightarrow ^{A-8}_{Z-4}\mathrm{D_5}\)
where \(Z,A\) are the atomic and mass number of element \(\mathrm{X},\) respectively. The possible emitted particles or radiations in the sequence, respectively are:
\(^A_Z \mathrm{X}\rightarrow ^{A-4}_{Z-2}\mathrm{D_1}\rightarrow ^{A-4}_{Z-1}\mathrm{D_2}\rightarrow ^{A-8}_{Z-3}\mathrm{D_3}\rightarrow ^{A-8}_{Z-4}\mathrm{D_4}\rightarrow ^{A-8}_{Z-4}\mathrm{D_5}\)
where \(Z,A\) are the atomic and mass number of element \(\mathrm{X},\) respectively. The possible emitted particles or radiations in the sequence, respectively are:
| 1. | \(e^+, \alpha, e^-, \alpha , \gamma \) | 2. | \(e^-, \alpha, e^+, \alpha , \gamma \) |
| 3. | \(\alpha ,e^-, \alpha, e^+, \gamma \) | 4. | \(\alpha ,e^+, \alpha, e^-, \gamma \) |
Subtopic: Â Types of Decay |
 68%
From NCERT
NEET - 2024
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Tritium is an isotope of hydrogen whose nucleus triton contains \(2\) neutrons and \(1\) proton. Free neutrons decay into\(p+e^{-1}+\nu^{-1}.\) If one of the neutrons in Triton decays, it would transform into \(\mathrm{He}^{3}\) nucleus. This does not happen. This is because:
| 1. | triton energy is less than that of a \(\mathrm{He}^{3}\) nucleus. |
| 2. | the electron created in the beta decay process cannot remain in the nucleus. |
| 3. | both the neutrons in Triton have to decay simultaneously resulting in a nucleus with \(3\) protons, which is not a \(\mathrm{He}^{3}.\) nucleus. |
| 4. | free neutrons decay due to external perturbations which is absent in the Triton nucleus. |
Subtopic: Â Types of Decay |
From NCERT
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When a nucleus in an atom undergoes a radioactive decay, the electronic energy levels of the atom:
| 1. | do not change for any type of radioactivity |
| 2. | change for \(\alpha\) and \(\beta\text-\)radioactivity but not for \(\gamma\text-\)radioactivity |
| 3. | change for \(\alpha\text-\)radioactivity but not for others |
| 4. | change for \(\beta\text-\)radioactivity but not for others |
Subtopic: Â Types of Decay |
 77%
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\({ }_{82}^{290} X \xrightarrow{\alpha} Y \xrightarrow{e^{+}} Z \xrightarrow{\beta^{-}} P \xrightarrow{e^{-}} Q\)
In the nuclear emission stated above, the mass number and atomic number of the product \(Q\) respectively, are:
1. \(286,80\)
2. \(288,82\)
3. \(286,81\)
4. \(280,81\)
In the nuclear emission stated above, the mass number and atomic number of the product \(Q\) respectively, are:
1. \(286,80\)
2. \(288,82\)
3. \(286,81\)
4. \(280,81\)
Subtopic: Â Types of Decay |
 68%
From NCERT
NEET - 2024
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An element \(A\) decays into element \(C\) by a two-step process
\(A\rightarrow B+_{2}^{4}\mathrm{He}\)
\(B\rightarrow C+2e^{-}\)
Then:
\(A\rightarrow B+_{2}^{4}\mathrm{He}\)
\(B\rightarrow C+2e^{-}\)
Then:
| 1. | \(A\) and \(C\) are isotopes |
| 2. | \(A\) and \(C\) are isobars |
| 3. | \(A\) and \(B\) are isotopes |
| 4. | \(A\) and \(B\) are isobars |
Subtopic: Â Types of Decay |
 65%
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In which of the following decays the atomic number decreases?
| (a) | \(\alpha\text-\)decay | (b) | \(\beta^{+}\text-\)decay |
| (c) | \(\beta^{-}\text{-}\)decay | (d) | \(\gamma\text-\)decay |
Choose the correct option:
| 1. | (a), (b) | 2. | (b), (c) |
| 3. | (c) | 4. | (a), (d) |
Subtopic: Â Types of Decay |
 89%
From NCERT
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In one \(\alpha \text-\) and \(2\beta^{-} \text-\)emissions:
| 1. | mass number reduced by \(2\) |
| 2. | mass number reduces by \(6\) |
| 3. | atomic number is reduced by \(2\) |
| 4. | atomic number remains unchanged |
Subtopic: Â Types of Decay |
 77%
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\(^{238}_{92}\mathrm{U}\) converts into \(^{206}_{82}\mathrm{Pb}\) by radio active decay process. How many \(\alpha\)-particles and \(\beta\)-particles may be emitted in the process?
| 1. | \(8\alpha~\text{and}~8\beta\) | 2. | \(5\alpha~\text{and}~12\beta\) |
| 3. | \(8\alpha~\text{and}~6\beta\) | 4. | \(6\alpha~\text{and}~8\beta\) |
Subtopic: Â Types of Decay |
 80%
From NCERT
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In the nuclear decay given below:
\({ }_{\mathrm{Z}}^{\mathrm{A}} \mathrm{X} \rightarrow { }_{\mathrm{Z}+1}^{\mathrm{A}} \mathrm{Y}\rightarrow { }_{\mathrm{Z-1}}^{\mathrm{A-4}} \mathrm{B}\rightarrow { }_{\mathrm{Z-1}}^{\mathrm{A-4}} \mathrm{B}\) the particles emitted in the sequence are:
\({ }_{\mathrm{Z}}^{\mathrm{A}} \mathrm{X} \rightarrow { }_{\mathrm{Z}+1}^{\mathrm{A}} \mathrm{Y}\rightarrow { }_{\mathrm{Z-1}}^{\mathrm{A-4}} \mathrm{B}\rightarrow { }_{\mathrm{Z-1}}^{\mathrm{A-4}} \mathrm{B}\) the particles emitted in the sequence are:
| 1. | \(\beta, \alpha, \gamma\) | 2. | \( \gamma, \beta, \alpha\) |
| 3. | \(\beta, \gamma,\alpha\) | 4. | \(\alpha,\beta, \gamma\) |
Subtopic: Â Types of Decay |
 90%
From NCERT
AIPMT - 2009
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