Physics

Nuclear and Atomic Physics

571 Questions

Nuclear and atomic physics explores the components and properties of the nucleus, including isotopes, radioactive decay, and fundamental forces. These concepts are essential for various competitive exams requiring a strong foundation in physics. The provided questions cover structural properties, mass, energy equivalence, and particle interactions.

Nucleus propertiesIsotopes and mass numberAlpha particle scatteringNuclear forcesMass energy equivalenceBeta particle emission

Nuclear and Atomic Physics Questions

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

When $ _{15}P^{30}$ decays to become  $ _{14}Si^{30}$, which particle is released ?

  1. electron
  2. $\alpha$-particle

  3. neutron

  4. positron
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The nuclear reaction :   $ _{15}P^{30}\rightarrow$   ${14}Si^{30} + $  $ _{+1}e^0$

Thus a positron is emitted during the decay of  $ _{15}P^{30}$ into   $ _{14}Si^{30}$.

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

What would be an atom that has lost an electron?

  1. Positron

  2. Negatron

  3. Baryon

  4. Hadron

  5. Ion
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

We know that an atom is electrically neutral because it has equal number of electrons(negative charge) and protons(positive charge) , now when it has lost an electron , negative charge decreases in the atom hence the net charge is now positive, the atom would be an ion.

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

The equation $ _{88}Ra^{226}\rightarrow _{86}Rn^{222}+ _{2}He^{4}$ emits which particle?

  1. $\beta$-decay
  2. $\alpha$-decay
  3. $\gamma$-decay

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$\alpha $ - decay 

When an unstable atomic nucleus emits two protons and two neutrons the radioactive process is known as alpha decay. 

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

During $\beta^-$ emission:

  1. a neutron in the nucleus decays emitting an electron

  2. an atomic electron is ejected

  3. an electron already present within the nucleus is ejected

  4. a part of the binding energy of the nucleus is converted into an electron

  5. a proton in the nucleus decays emitting an electron
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$\beta^-$ emission is due to decay of neutron in the nucleus $n\rightarrow p+e^-$.

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

$ _{84}P _{0}^{210}$ originally at rest emits $\alpha $- particles of KE 'K' Find  the KE of recoiling nucleus:

  1. $\dfrac{4}{214}K$
  2. $\dfrac{4}{206}K$
  3. $\dfrac{K}{206}$
  4. $\dfrac{K}{214}K$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$84P _o^{210}\xrightarrow 82Pb^{206}+\alpha \Rightarrow $ mass of remaining nucleus $(Pb)=206$

Initial momentum =$0$ (initial Po was at rest)
Momentum of $\alpha$- particle carrying $KE=K$
$P _1\sqrt{2m _{\alpha}k}$     $m _{alpha}=4n$,mass of $\alpha$
$P _1=\sqrt{8k}$
from conservation of momentum
$P _1+P _2=0$
$\Rightarrow P _1^2=P _2^2$
$2\ mrk'=2k$
$K'=\dfrac{4k}{mr}=\dfrac{4k}{206}$

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

When a radioactive nucleus emits a $\beta $- particular, the proton- neutron ratio

  1. decreases

  2. increases

  3. remains same

  4. first decreases and increases
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When the neutron to proton ratio in the nucleus is too great a beta particle is emitted. In basic beta decay a neutron is transformed into a proton and an electron. The electron is then emitted as a beta particle which increases the atomic number by one and the molar mass is unchanged.

Hence, the proton- neutron ratio increase.

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

The radius of spherical nucleus as measured by electron scattering is 36. fm. what is the likely mass number of the nucleus?

  1. 27

  2. 40

  3. 56

  4. 120
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Nuclear radius R = R0 * A^(1/3), where R0 is approx 1.2 fm. 36 = 1.2 * A^(1/3). A^(1/3) = 30. A = 30^3 = 27000. This calculation suggests the value 36 fm is very large. If R0 = 1.2, A = 27 is R = 1.2 * 3 = 3.6 fm. The question likely meant 3.6 fm.

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

When $ _{3}Li^{7}$ nuclei are bombarded by protons, and the resultant nuclei are $ _{4}Be^{8}$ , the emitted particles will be.   

  1. alpha particles

  2. beta particles

  3. gamma photons

  4. neutrons
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$ _{3}Li^{7} + ^{1} _{1}P \Rightarrow  _{4}Be^{8} + _{0}^{0}\gamma (energy)$
As, the emitted particles is only energy and gamma photons radiation is nothing but energy so, option  C is correct.

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

Which of the following assertions are correct?

  1. A neutron can decay to a proton only inside a nucleus

  2. A proton can change to a neutron only inside nucleus

  3. An isolated neutron can change into a proton

  4. An isolated proton can change int a neutron
Reveal answer Fill a bubble to check yourself
B,C Correct answer
Explanation

$\beta^{+}$ decay cannot occur in an isolated proton because it requires energy due to the mass of the neutron being greater than the mass of the proton. $\beta^{+}$ decay can only happen inside nuclei when the daughter nucleus has a greater binding energy.


an isolated neutron is not stable outside hence it decays emitting a proton.

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

If $ _{5}\textrm{B}^{11}$ converts into $ _{6}\textrm{C}^{11}$, then the particle emitted in this process will be 

  1. electron

  2. proton

  3. neutron

  4. positron
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
$\beta ^-$ minus decay produces an electron and electron anti neutrino.
$\beta ^-$ decay increases the proton by $1$ and reduces the neutron number by $1$
Hence, mass number remains same but atomic number increase by $1.$
Multiple choice physics nuclear physics beta decay change in nucleus due to radioactive decay alpha, beta and gamma particles (rays) and their properties

The particle emitted in the nuclear reaction 
$ _{z}\textrm{X}^{A}$ = $ _{z+1}\textrm{Y}^{A}$ + ..... will be 

  1. $\alpha$ -particle
  2. $\beta^{-}$ -particle
  3. $\beta{+}$ -particle
  4. $Photon$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
In $\beta^{-}$ decay, there is a gain of one proton and an anti-neutrino is emitted from nucleus, hence atomic number is increased by 1 and weight remains same.