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 motion, force and speed contact and non-contact forces comparing force in magnetic, electric and gravitational fields identifying forces

Let E,G and N represents the magnitude of electromagnetic, gravitational and nuclear forces between protons and electrons at a given separation (1 fermi meter). Then

  1. N < E < G

  2. E > N > G

  3. G > N > E

  4. N > E > G
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$r=1fermimeter$ which is same for all.
$F _e=\frac{k _eq _1q _2}{r^2}  ;F _g=\frac{Gm _1m _2}{r^2}$ ; 
$F _N=\frac{\alpha}{r^2}$
where$k _e=8.988\times10^9 N^2m^2c^{2} $;
$q _1=-1.6\times10^{-19}c$; 
$q _2=1.6\times10^{19}$;
$G=6.67\times10^{-11}m^3kg^{-1}s^2$;
$m _1=9.1\times10^{-31}kg$; 
$m _2=1.67\times10^{-27}kg$;
$\alpha=2.3103\times10^{-28}$
$F _e=2.307\times10^{-28}$  ; ${F _g}=1.868 \times10^{-64}$ ;
$F _N=2.3103 \times10^{-28}$
hence,$F _N>F _e>F _g$


Multiple choice chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

An αα particle is:

  1. a hydrogen molecule

  2. a helium nucleus

  3. an electron

  4. a proton
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$(B)$ a helium nucleus 


$Reason$ : An $\alpha$ particle is a positively charged particle consists of two protons and two neutrons , all held together by the same strong nuclear force that binds the nucleus of any atom , emitted by some radioactive substances and identical to the nucleus of helium atom . It carry a charge of $+2$. 

Multiple choice chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

Which of the following has negative charge and is present in atom as pairs with opposite spin?

  1. Proton

  2. Neutron

  3. Electron

  4. Isotope

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

Option $C$ is the correct answer.

An electron is a negatively charged particle. In an orbital, if two electrons are present together, they should and must have opposite spins. Because, no two electrons can be identically same.

Multiple choice chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

What are nucleons?

  1. the sum of protons and neutrons present in the nucleus.

  2. the number of protons in the nucleus.

  3. the number of neutrons in the nucleus.

  4. the sum of protons, neutrons and electrons present in the nucleus.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A nucleon is one of either of the two types of subatomic particles (neutrons and protons) which are located in the nucleus of atoms.
Only option A correct .

Multiple choice chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

Positronium is the name given to an atom-like combination formed between_____________.

  1. a positron and a proton

  2. a positron and a neutron
  3. a positron and an $\alpha$-particle

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

Positronium is the name given to an atom-like combination formed between a positron and an electron. Electron  and positron are particle and antiparticle.

Multiple choice chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

Select the correct statement?

  1. An atom has equal number of electrons and protons.

  2. An atom has equal number of electrons and neutrons.

  3. An atom has equal number of protons and neutrons.

  4. An atom has equal number of electrons, protons and neutrons.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

An atom is electrically neutral as it has an equal number of electrons and protons, that is, an equal number of negative and positive charges. 


In order to become stable, atom loses or gains one or more electrons and forms an ion which carries a charge.

Hence the correct option is A.

Multiple choice chemistry the periodic table dobereiner's triads development of the modern periodic table into the history

When a Dobereiner triad is considered, the sum of atomic weights of extreme elements X and Z is 177.6 and difference of Z and Y is five times the number of protons present in a neon atom. Identify X, Y and Z.

  1. $X \rightarrow Ca, Y \rightarrow Sr, Z \rightarrow Ba$
  2. $X \rightarrow Li, Y \rightarrow Na, Z \rightarrow K$
  3. $X \rightarrow K, Y \rightarrow Rb, Z \rightarrow Cs$
  4. $X \rightarrow Sr, Y \rightarrow Ba, Z \rightarrow Ra$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The atomic weight of Y is avergae of X and Z
$\therefore { M } _{ Y }=\cfrac { 177.6 }{ 2 } =88.8$
$88.8$ is weight of Sr. So Y is Sr. According to this only option A is correct.
Multiple choice chemistry structure of the atom neutrons discovery of neutrons structure of atoms

Which of the following statements is false?

  1. Proton has a positive charge

  2. Neutron has no charge

  3. Electrons are found in regions of the atom called orbitals

  4. Electrons has a greater mass than the protons

  5. Protons and neutrons form the nucleons of the atom
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Electron has less mass. A proton and a neutron have effectively the same mass. A proton (or a neutron) has approximately 1837 times more massive than an electron.
Multiple choice chemistry structure of the atom neutrons discovery of neutrons structure of atoms

$ _{7}{X}^{15}$ and $ _{8}{Y}^{15}$ differ in

  1. Physical properties

  2. Chemical properties

  3. Number of neutrons

  4. Number of nucleons
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The option (C) is the correct answer.
$\displaystyle _{7}{X}^{15}$ and $\displaystyle _{8}{Y}^{15}$ differ in number of neutrons.
Number of neutrons for $\displaystyle _{7}{X}^{15} = 15-7=8$
Number of neutrons for $\displaystyle _{8}{Y}^{15}=15*8=7$
Note: Number of neutrons $\displaystyle =$ mass number $\displaystyle -$ atomic number.