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

Which of the following statements was included in Thomson's model of an atom?

  1. Nuclear arrangement in atom

  2. Neutrality of an atom

  3. Presence of neutron

  4. Nuclear size compared to atom

  5. Revolution of electrons around nucleus
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Thomson's model explained that an atom is electrically neutral as the number of protons and electrons in an atom are equal and the charge on an electron is equal in magnitude but opposite in nature to the charge on a proton.

Multiple choice

The nucleus of an atom consists of

  1. electrons

  2. neutrons

  3. protons and neutrons

  4. protons, neutrons and electrons
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The nucleus contains protons (positively charged) and neutrons (neutral), which together form the dense core of an atom. Electrons orbit around the nucleus in electron shells, not within it. Option D incorrectly includes electrons in the nucleus, while options A and B only mention one component each.

Multiple choice

In case of the neutral atoms, two isotopes differ in the number of

  1. electron shells

  2. protons

  3. valance electrons

  4. neutrons

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. This difference in neutron count gives isotopes different mass numbers while maintaining identical chemical properties. Electron shells and valence electrons remain the same in neutral isotopes.

Multiple choice

In an atomic nucleus, neutrons and protons are held together by

  1. gravitational forces

  2. magnetic forces

  3. strong forces

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

The strong nuclear force is the fundamental force that binds protons and neutrons together in the atomic nucleus. It overcomes the electromagnetic repulsion between positively charged protons and is approximately 100 times stronger than electromagnetic forces at nuclear distances. Gravitational forces are negligible at this scale, while magnetic and coulombic forces are electromagnetic in nature.

Multiple choice

Atoms with the same mass number, but different nuclear charges are called ___________.

  1. isotopes

  2. isobars

  3. isochores

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

Isobars are atoms with the same mass number (total nucleons) but different atomic numbers (different numbers of protons). Isotopes have the same atomic number but different mass numbers. Isotones have the same number of neutrons. Isochores relate to constant volume in thermodynamics.

Multiple choice

The most massive and solid part of the atom is ___________.

  1. proton

  2. electron

  3. neutron

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

The nucleus contains protons and neutrons (collectively called nucleons), which account for over 99.9% of an atom's mass. Electrons orbit the nucleus and have negligible mass (about 1/1836 of a proton). Therefore, the nucleus is both the most massive and solid (densest) part of the atom.

Multiple choice

Nucleus consists of ___________.

  1. electrons

  2. protons

  3. neutrons

  4. both protons and neutrons

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The atomic nucleus is composed of protons (positively charged) and neutrons (neutral), collectively called nucleons. These particles are bound together by the strong nuclear force. Electrons orbit the nucleus in electron shells and are not part of the nucleus itself.

Multiple choice

Nuclear forces are ____.

  1. the weakest in nature

  2. the strongest in nature

  3. negligible in nature

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Nuclear force is the strongest of the four fundamental forces in nature, much stronger than electromagnetic, gravitational, and weak nuclear forces. It acts between nucleons (protons and neutrons) at very short ranges (~1 fm) and is responsible for holding the nucleus together despite the repulsive electromagnetic force between protons.

Multiple choice

Directions: This question presents a sentence, all or part of which is underlined. Beneath the sentence you will find five ways of phrasing the underlined part. The first of these repeats the original; the other four are different. If you think the original is best, choose the first answer; otherwise choose one of the others.

Very occasionally a neutrino will collide with a neutron in a chloride nucleus, turning the latter into a proton and simultaneously turning the chlorine atom to radioactive argon.

  1. turning the latter into a proton and simultaneously turning the chlorine atom to radioactive argon

  2. turning the latter to a proton and simultaneously turning the chlorine atom to radioactive argon

  3. turning the later into a proton and simultaneously turning the chlorine atom to radioactive argon

  4. turning the latter into a proton and simultaneously turning the chlorine atom into radioactive argon

  5. turning the later into a proton and simultaneously turning the chlorine atom into a radioactive argon
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

'Turning' is followed by 'into'.  The error stands corrected in option (4).

Multiple choice

Number of neutrons in 92X238 is

  1. 144

  2. 148

  3. 242

  4. 146
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

For X-238 with atomic number 92, neutrons = mass number - atomic number = 238 - 92 = 146. This element is uranium (U-238). Option A (144) would give mass 236, B (148) gives 240, and C (242) is the mass number itself.

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 10-5 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 10-14 m. The total number of nucleons determines the atomic mass of an atom. Here, both the statements are incorrect.

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 exited.

  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 and 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 not correct?

  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 1011coulomb per kilogram.

  4. It is deflected in both 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 coulombs per kilogram.