Nucleus MCQ Quiz - Objective Question with Answer for Nucleus - Download Free PDF

Concept:

Average Mass of an Element with Isotopes:

• The average mass of an element with isotopes is calculated by taking the weighted sum of the masses of the isotopes, weighted by their relative abundances.
• If there are three isotopes A, B, and C with masses m₁, m₂, and m₃, and relative abundances in the ratio 2:3:5, the average mass of the element (M) is given by:
• M = (relative abundance of A) × m₁ + (relative abundance of B) × m₂ + (relative abundance of C) × m₃
• The relative abundances are given in the ratio 2:3:5, which means:
  Abundance of A = 2/(2+3+5), Abundance of B = 3/(2+3+5), Abundance of C = 5/(2+3+5).
• By applying these abundances, the formula for the average mass becomes:
  M = 0.2m₁ + 0.3m₂ + 0.5m₃

Calculation:

Given,

Relative abundances of isotopes A, B, and C are in the ratio 2:3:5.

The total sum of the relative abundances is: 2 + 3 + 5 = 10

The relative abundance of isotope A is 2/10 = 0.2, for isotope B is 3/10 = 0.3, and for isotope C is 5/10 = 0.5.

The average mass of the element is calculated as:

Average mass = 0.2m₁ + 0.3m₂ + 0.5m₃

∴ The average mass of the element is 0.2m₁ + 0.3m₂ + 0.5m₃.
Hence, the correct option is 1) 0.2m₁ + 0.3m₂ + 0.5m₃.

Key Points

• Gobar Gas is a renewable source of energy produced from organic waste material such as animal dung.
• The process of producing Gobar Gas involves the anaerobic digestion of organic material, which produces biogas primarily composed of methane and carbon dioxide.
• Gobar Gas is used for various purposes such as cooking, heating, and generating electricity.

Additional Information

• Nuclear Energy
  • Nuclear energy is generated through nuclear reactions, typically through nuclear fission, where the nucleus of an atom splits into smaller parts.
  • This process releases a large amount of energy, which is used to generate electricity in nuclear power plants.
  • While it is a powerful energy source, it produces radioactive waste that requires careful handling and disposal.
• Geo-Thermal Energy
  • Geo-thermal energy is derived from the heat stored beneath the Earth's surface.
  • This energy is harnessed by tapping into underground reservoirs of hot water or steam to generate electricity or for direct heating applications.
  • It is a renewable and sustainable energy source with minimal environmental impact.
• Hydro-Energy
  • Hydro-energy, or hydroelectric power, is produced by capturing the kinetic energy of flowing or falling water.
  • This energy is converted into mechanical energy by a turbine and then into electricity by a generator.
  • It is a clean and renewable energy source that does not produce direct waste or pollutants.

Ans.(2)

Sol.

Oxygen \({ }_{8}^{16} \mathrm{O}\) has 8 protons and 8 neutrons.

mass of electron, m_e = 0.00055u

mass of proton, m_p = 1.00727u

mass of neutron, m_n = 1.00866u

experimental mass of nucleus 15.99053u

1u = 931.5 MeV/c²

Mass defect, ΔM = 8 m_p + 8 m_n - M_N

∴ ΔM = 8(1.0078) + 8(1.0087) - 15.99053

= 0.137u

= 0.137 × 931.5 = 127.5 MeV/c²

The correct answer is: Option 1) strong, short range and charge independent

Explanation:

Nuclear forces are the forces that act between the protons and neutrons within an atomic nucleus.

These forces are characterized by the following properties:

Strong: Nuclear forces are one of the strongest forces in nature, significantly stronger than electromagnetic forces.

Short Range: Nuclear forces are effective only over very short distances, typically on the order of a few femtometers (10^-15 meters).

Charge Independent: Nuclear forces act equally between pairs of neutrons, pairs of protons, and neutron-proton pairs, meaning they do not depend on the charge of the particles.

Therefore, the correct statement describing nuclear force is that it is strong, short-range, and charge independent.

The correct answer is option 1) i.e. 2:1

CONCEPT:

• Nuclear Radius: The radius of a nucleus (R) is related to its mass number (A) by the empirical formula:

R = R_0 A^{1/3}

where:

• R is the radius of the nucleus
• R₀ is a constant (approximately 1.2 fm)
• A is the mass number

CALCULATION:

Given that:

Mass number of A (Aₐ) = 216

Mass number of B (A_b) = 27

The ratio of the nuclear radii (rₐ/r_b) can be calculated as follows:

\(\frac{rₐ}{r_b} = \frac{R_0 Aₐ^{1/3}}{R_0 A_b^{1/3}} = \left(\frac{Aₐ}{A_b}\right)^{1/3}\)

Substituting the given values:

\(\frac{rₐ}{r_b} = \left(\frac{216}{27}\right)^{1/3} = \left(8\right)^{1/3} = 2 \)

Thus, the ratio of the nuclear radii (rₐ/r_b) is 2:1.

The correct answer is isotones.

CONCEPT:

• The nuclei have been classified based on the number of protons (atomic number) or the total number of nucleons (mass number) as follows:

EXPLANATION:

• From the above, it is clear that nuclei having the same number of neutrons but a different mass number are called isotones. Therefore option 3 is correct.

The correct answer is Higgs boson.

Key Points

• God Particle spotted on 4-7-2012 is also called Higgs boson.
• Higgs boson is an elementary particle in the Standard Model of particle physics.
• It is produced by the quantum excitation of the Higgs field.
• Higgs's idea was that the universe is bathed in an invisible field similar to a magnetic field. Every particle feels this field—now known as the Higgs field.

Important Points

• Noble prize in 2013 in physics had been given in the field of Universe.
• Two scientists had won the Nobel prize in physics for their work on the theory of the Higgs boson.
• Peter Higgs, from the UK, and Francois Englert from Belgium, had shared the prize.
• In the 1960s, they were among several physicists who proposed a mechanism to explain why the most basic building blocks of the Universe have mass.
• The mechanism predicts a particle - the Higgs boson - which was finally discovered in 2012 at the Large Hadron Collider (LHC) at Cern, in Switzerland.

The correct answer is Strong nuclear force.

Key Points

• Strong nuclear forces are responsible for holding the nuclei of atoms together. This is the most dominant force in reactions and is so strong that it binds protons with similar charges with the nucleus.
• It is the most attractive in nature but can be repulsive sometimes. It has a very short range of just 1fm.

Additional Information

• Fundamental forces or interactions are those forces of nature as without them all things will fall apart.
• There are four fundamental forces of nature. These are as follows:

1. Gravitational Force
2. Electromagnetic Force
3. Weak Nuclear Force
4. Strong Nuclear Force

CONCEPT:

• The Atomic mass is the sum of protons and neutrons.

• In the nucleus of an atom, there are protons and neutrons.

Number of protons = Atomic number of an element.

Nuclei = neutron + proton

EXPLANATION:

Given that: mass number = 23 and atomic number = 11.

Number of protons = Atomic number = 11

IMPORTANT POINTS:

• Sodium is a chemical element with Atomic number 11 and Symbol Na.
• Mass number = Number of protons + Number of neutrons, hence the number of neutrons is 12.

• Isotopes are elements having different numbers of neutrons and the same number of protons.

CONCEPT:

Greenhouse effect:

• The greenhouse effect is a natural process that warms the Earth's surface.
• When the Sun's energy reaches the Earth's atmosphere, some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases.
• That trapping of heat is known as the greenhouse effect.

EXPLANATION:

• Carbon dioxide prevents solar radiations to go back into space.
• It absorbs the solar rays and energy of the sun due to which the temperature on the earth increases and natures balance gets disturbed.

• Therefore, absorption occurs due to the presence of water vapour, carbon dioxide, and ozone in the atmosphere and other particulate matter.

Green House Gases (GHG):

The major greenhouse gases are

• Water vapour - causes about 36% - 70% of the greenhouse effect
• Carbon dioxide (CO2) which causes 9 - 26%
• Methane (CH4) causes 4 - 9% and ozone (O3)

CONCEPT:

In an atom's notation, _ZX^A ; z is an atomic number and A is the mass number.

No. of protons Z 

No of neutrons = A - Z 

EXPLANATION:

The helium atom is presented by ₂He⁴

Z = 2 and A = 4

No. of protons Z = 2

No of neutrons = A - Z = 2

So the correct answer is option 2.

CONCEPT:

• ATOMIC NUMBER: It is defined as the number of protons present in the nucleus. It is denoted by letter Z.
• MASS NUMBER: The total number of protons and neutrons present in a nucleus is called the mass number of the element. It is denoted by letter A.

• For neutral atom,

1. Number of protons in an atom = Z
2. Number of electrons in an atom = Z
3. Number of nucleons in an atom = A
4. Number of neutrons in an atom = N = A – Z

CALCULATION:​

• From above it is clear that the number of neutrons equal to the difference of a mass number and atomic number.

Concept:

• The electrons, protons, and neutrons are the three main fundamental particles of an atom of a molecule. 

• In the nucleus of an atom, there are protons and neutrons.
• The electrons revolve around the nucleus of the atom.

The number of protons = Atomic number of an element.

Nuclei = neutron + proton

Explanation:

• The neutron was discovered by Chadwick in February 1932.
• The electron was discovered by J.J. Thomson in 1897.
• The proton was discovered by Ernest Rutherford in 1920.

CONCEPT:

Bio-mass energy:

• Bio-mass is the energy source that is received from animal wastes and plant materials.
  • For example, cow-dung, various plant materials like the residue after harvesting the crops, vegetable waste, and sewage are decomposed in the absence of oxygen to give biogas.

EXPLANATION:

• From the above, it is clear that wood, gobar-gas, and cow-dung are an example of biomass energy sources. Therefore option 1^st, 2^nd, and 4^th is not a bio-mass energy source.
• On the other hand, nuclear energy is obtained from nuclear fusion and fission. Therefore option 3^rd is the answer.

CONCEPT:

• Mass energy equation: This equivalence of mass and energy is a consequence of Einstein’s theory of special relativity.
  • Which simply means that mass can be converted into energy and visa-versa.
  • According to this equivalence, mass and energy are inter-convertible.
  • So whenever you have mass, it means you have got lots of energy just sitting inside. 

This is given in Einstein’s famous relation:

E = mc²

Where m is the mass in kilograms, c is the velocity of light in a vacuum c ≅3×10⁸ m/s.

EXPLANATION:

• From the above equation its clear that the equation for mass-energy relation was given by Albert Einstein.

The correct option is 2.