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 chemistry what is inside atom discovery of neutrons structure of atoms discovery of subatomic particles

A neutron has :

  1. positive charge

  2. negative charge

  3. no charge

  4. all of above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The neutron is a subatomic particle with no net electric charge and a mass slightly larger than that of a proton. Protons and neutrons, each with mass approximately one atomic mass unit, constitute the nucleus of an atom, and they are collectively referred to as nucleons.

Multiple choice chemistry what is inside atom discovery of neutrons structure of atoms discovery of subatomic particles

Which of the following is the main cause of late discovery of neutron?

  1. Neutron is highly unstable particle

  2. Neutron in nucleus moves very fast

  3. Neutron is charge-less particle

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Initially it was believed that the atom consisted of a small massive nucleus with positive charge surrounded by a much larger cloud of negatively charged electrons. Being charge-less particle, neutron did not show their influence in experiments performed for discovery of charged particles electrons and protons.

Multiple choice chemistry what is inside atom discovery of neutrons structure of atoms discovery of subatomic particles

Which of the following reactions led to the discovery of neutron?

  1. $ _6^{12}C+ _1^1H\rightarrow _7^{14}N+ _0^In$
  2. $ _{11}^{5}C+ _1^2D\rightarrow _{6}^{12}C+ _0^In$
  3. $ _4^{9}Be+ _2^4He\rightarrow _6^{12}C+ _0^1n$
  4. $ _4^{8}C+ _2^4He\rightarrow _6^{11}C+ _0^1n$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In 1930 it was discovered that Be bombarded by alpha particles and emitted stream of radiation. In 1932 Chadwick proposed that the particle is Rutherford's neutron.

$ _{ 2 }^{ 4 }{ \alpha  }+ _{ 4 }^{ 9 }{ Be }\rightarrow _{ 6 }^{ 12 }{ C }+ _{ 0 }^{ 1 }{ n }$

Multiple choice chemistry what is inside atom discovery of neutrons structure of atoms discovery of subatomic particles

The neutron is a neutral (non-electrical) particle in the centre of the atom. It was discovered when a tiny piece of the metal, beryllium, was bombarded with alpha particles. This discovery was made by:

  1. Chadwick

  2. Rutherford

  3. Niels Bohr

  4. Enrico Fermi
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
In 1930, it was discovered that Beryllium, when bombarded by alpha particles, emitted a very energetic stream of neutral radiation. In 1932, Chadwick proposed that neutral radiation consists of a new type of neutral particles - neutrons.
Multiple choice physics types of energy law of conservation of energy the law of conservation of energy work, energy and machines

A thorium nucleus emits an alpha particle. Which of the following fundamental physics principles can be used to explain why the direction of the daughter nucleus recoil must be in the opposite direction of the alpha emission?
I. Newtons third law
II. Conversation of momentum
III. Conversation of energy

  1. Only II

  2. Only III

  3. I and II only

  4. II and III only
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

By Newton's third law of motion, every action has equal and opposite reaction. Hence, the direction of the daughter nucleus recoil must be in the opposite direction to the direction of the alpha emission.


By law of conservation of momentum, the net momentum of the system should remain constant as no external force is acting on the system. Hence, momentum of the daughter nucleus must be opposite to the direction of the alpha particle so that the net momentum of the system remains zero.

By law of conservation of energy, the total energy of an isolated system remains zero. It cannot be used to conclude the direction of motion of the particles.

Multiple choice chemistry d- and f-block elements actinoids the actinoids the d-and f-block elements comparison of lanthanoids and actinoids

The actinide contraction is due to:

  1. perfect shielding of $5f$ election
  2. imperfect shielding of $4f$ election
  3. imperfect shielding of $5f$ electron
  4. perfect shielding of $4f$ election
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The actinide contraction is due to imperfect shielding of $5f$ electron. The valence shell electronic configuration of actinoids is $\displaystyle 5f^{1-14}6d^{0-1}7s^2$. With an increase in atomic number, the positive charge on the nucleus increases by $+1$, and one more electron enters in the same $5f$ subshell. There is imperfect shielding of one electron by another electron in the same $5f$ subshell. Due to this, the atomic and ionic radii show a gradual decrease with increase in atomic number.

Multiple choice physics energy production hazards and safety measures of radiations harmful effects and safety precautions for radiations nuclear physics

In the process of Radio active decay the correct example is _____.

  1. $ _6C^{14} \xrightarrow[of \,\propto \,particle]{emission} { _7C^{15}}$
  2. $ _6C^{14} \xrightarrow[of \,\propto \,particle]{emission} { _7N^{15}} + 1e$
  3. $ _6C^{14} \xrightarrow[of \,\propto \,particle]{Absorption} { _7N^{15}}$

  4. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Carbon-14 decay involves beta emission, not alpha emission. The provided options contain incorrect nuclear equations (e.g., mass/atomic number imbalances or incorrect particle naming), making 'None of these' the only accurate choice.

Multiple choice chemistry the structure of the atom discovery of charged particles the plum pudding atom discovery of electrons and protons

The fraction occupied by nucleus in an atom is:

  1. $1/10^{-10}$
  2. $1/10^8$
  3. $1/10^{-5}$
  4. $1/10^5$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Radius of atom $\displaystyle  = 10^{-10}$ m
Radius of nucleus $\displaystyle  = 10^{-15}$ m
The fraction occupied by nucleus in an atom $\displaystyle  = \dfrac {10^{-15}}{10^{-10}}=\frac {1}{10^5}$
Multiple choice chemistry the structure of the atom discovery of charged particles the plum pudding atom discovery of electrons and protons

Which of the following elements has maximum density of nucleus?

  1. ${ { _{ 14 }{ Si } } }^{ 30 }$
  2. ${ { _{ 15 }{ P } } }^{ 31 }$
  3. ${ { _{ 8 }{ O } } }^{ 16 }$

  4. All have same desity
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
 $Element$  $Atomic$ $number$$(A)$  $Atomic$ $mass$ $number$$(Z)$ no. of proton (A) no. of neutron(2A-Z)
 $Si$  14  30  14  16
 $P$  15  31 15  16 
 $O$  8  16  8  8

The element containing greater number of proton and neutron has greater density, phosphorus has highest density as compared to others.

$P>Si>O$