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

A student of class 10 of ICSE board gives the clues in the form of reasons for the emission of beta particle to one of his classmates who recently studied the chapter of modern physics. Which of the following clues should he choose to reach the correct reason for this?

  1. An electron of outer orbit comes out of an atom after being excited.

  2. A proton disintegrates into neutron and electron, and this electron comes out of an atom.

  3. A neutron disintegrates into proton and electron, and this electron comes out of an atom.

  4. An electron of inner orbit falls into the nucleus, and finally comes out of an atom.

  5. A neutron strikes the electron of inner orbit and expels it out as a beta particle.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

An atom in which the ratio of neutrons to the protons exceeds unity is unstable. A neutron disintegrates into proton and electron, and this electron comes out of an atom.

Multiple choice

Which of the following information about an alpha particle is incorrect?

  1. The mass of an alpha particle is 6.68 x 10-27 kg.

  2. Its charge is + 3.2 x 10-19 coulomb.

  3. Its specific charge is 1.76 x 1011 coulomb per kilogram.

  4. It is deflected in both an electric and magnetic field.

  5. It is used for transmutation.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The specific charge of an alpha particle is 4.79 x 107 coulomb per kilogram.

Multiple choice

Which of the following statements are incorrect for a nucleus of an atom?

(a) The size of nucleus is of the order of 10-14 m. (b) It contains nucleons naming proton and neutron. (c) The total number of nucleons determines its atomic number. (d) The mass of nucleus of an atom is approximately equal to the product of its mass number and the number of proton.

  1. Both (a) and (b)

  2. Both (b) and (c)

  3. Both (c) and (d)

  4. Both (a) and (c)

  5. Both (b) and (d)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The size of a nucleus is of the order 10-15 m. The total number of nucleons determines the atomic mass of an atom. Here, both the statements are incorrect.

Multiple choice

A proton is 1840 times heavier than an electron. When it is accelerated by a potential difference of 1 kV, its kinetic energy will be

  1. 1 keV

  2. 10.2 keV

  3. 102.3 keV

  4. 1840 keV

  5. 1/1840 keV
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The kinetic energy or energy acquired by the electron on being accelerated by a potential difference of 1 kV = 1keV Moreover, as proton has the same charge and energy, Potential difference × charge = 1 keV Hence, proton will have the same kinetic energy.

Multiple choice

Neutron

  1. 1960

  2. 1930

  3. 1932

  4. 1940
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The neutron was discovered by James Chadwick in 1932 at the Cavendish Laboratory in Cambridge. Chadwick's work resolved a mystery about atomic mass and led to our modern understanding of atomic structure.

Multiple choice

Which of the following factors affect the ionisation potential?

  1. Atomic number and number of neutrons

  2. Atomic size and nuclear charge

  3. Number of valence electrons and atomic weight

  4. Number of neutrons and mass number

  5. Number of protons and relative atomic mass
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ionisation potential is the energy required to remove one or more electrons from the outermost orbit of an isolated gaseous atom. The smaller the size of the atom, the more difficult it becomes to remove the valence electron due to the attraction of the nuclear charge on the electrons.

Multiple choice

The increasing order of effective nuclear charge is

  1. Na < Mg < Al < Si

  2. Mg < Na < Al < Si

  3. Mg < Mg < Si < Al

  4. Al < Mg < Na < Si

  5. Si < Al < Mg < Na
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

On moving from left to right in a period, effective nuclear charge increases with increase in atomic number. Thus, correct order of effective nuclear charge is Na < Mg < Al < Si.

Multiple choice

Which of the following affects the ionization energy?

  1. The atomic radius

  2. Nuclear charge

  3. Number of electrons in the inner shell

  4. Option 1) , 2) and 3) are correct

  5. Option 1) and 2) are correct
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Yes , it is correct as all the three options affect the Ionization energy.of an element.

Multiple choice

Neutron (n) discovered by

  1. J.J. Thompson by

  2. Chadwick

  3. Goldstein

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

James Chadwick discovered the neutron in 1932 through experiments involving alpha particle bombardment of beryllium. J.J. Thompson discovered the electron, Goldstein discovered the proton (canal rays), and Yukawa proposed the meson theory. Chadwick's discovery completed the picture of the three main subatomic particles.

Multiple choice

Point out the incorrect statement

I. Neutrons have about the same mass as protons but no electric change

II. Neutrons occur in the nuclei of all atoms

III. Neutrons and protons affect the chemistry of an atom

IV. Neutrons and electrons affect the chemistry of an atom

  1. I & II

  2. II & III

  3. III & IV

  4. I & IV
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Neutrons have nearly the same mass as protons but no electric charge (I is correct). Neutrons occur in ALL atomic nuclei except protium (II is correct). Protons and neutrons determine the nucleus, but only electrons participate in chemical bonding (III is incorrect, IV is also incorrect - neutrons do not affect chemistry).

Multiple choice

In which of the following processes, a proton is converted into a neutron?

  1. Positron emission

  2. Proton emission

  3. Neutron emission

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

Positron emission is a type of beta decay in which a proton is converted, via the weak force, to a neutron, releasing a positron (the antimatter counterpart of an electron) and a neutrino. Isotopes which undergo this decay and thereby emit positrons include carbon-11, potassium-40, nitrogen-13, oxygen-15, fluorine-18, and iodine-121.

Multiple choice

Nucleus contains

  1. electron only

  2. proton only

  3. proton and neutron

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

The atomic nucleus contains protons (positively charged) and neutrons (neutral). Electrons orbit outside the nucleus. The number of protons determines the element's identity, while neutrons contribute to nuclear stability and create isotopes.