Physics

Nuclear and Atomic Physics

576 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 nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

For making atom bomb, what else is needed except $U^{235}$?

  1. neutron

  2. proton

  3. electron

  4. meson
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The fission of $U-235$ in reactors is triggered by the absorption of a low energy neutron, often termed a "slow neutron" or a "thermal neutron". Other fissionable isotopes which can be induced to fission by slow neutrons are plutonium$-239,$ uranium$-233$, and thorium$-232$.
Multiple choice chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

The number of fissions of $^{235}U _{92}$ required to a produce a power of $1\ W$ is :

  1. $3.1\times 10^{10}$
  2. $3.1\times 10^{13}$
  3. $3.1\times 10^{19}$
  4. $3.1\times 10^{8}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

1 Watt = 1 Joule/second. Energy per fission of U-235 is approx 200 MeV = 3.2 * 10^-11 J. Fissions per second = 1 / (3.2 * 10^-11) = 3.125 * 10^10.

Multiple choice chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

A proton and a neutron are both shot at $100 ms^{-1}$ towards a $ _6^{12}C$ nucleus. Which particle, if either, is more likely to be absorbed by the nucleus?

  1. The proton

  2. The neutron

  3. Both particles are about equally likely to be absorbed

  4. Neither particle will be absorbed
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Proton will be experiencing repulsive forces because of presence of positive charges in the nucleus.
Hence, nucleus is more likely to be absorbed.

Multiple choice difference between interference and diffraction explaining wave phenomena diffraction

A metal plate is placed 2 m away from a monochromatic light source of 1 mW power. Assuming that an electron in metal collects its energy from a circular area of the plate as large as 10 atomic diameters (${10^{ - 9}}\;m$) in radius, calculate how long it will take for such a 'target' to 'soak off' % eV of energy for its emission from the metal?

  1. 1.5 hr

  2. 2.5 hr

  3. 3.5 hr

  4. 4.5 hr
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The power is spread over a sphere of area 4π(2)^2 = 16π m^2 at distance 2m. The electron collects from area π(10^-9)^2 m^2, so the fraction is 10^-18/16 = 6.25×10^-20. Power on target = 1 mW × 6.25×10^-20 = 6.25×10^-23 W. For 5 eV (5 × 1.6×10^-19 J), time = 8×10^-19 / 6.25×10^-23 ≈ 12800 s ≈ 3.5 hr. The question likely meant 5 eV (typo: % eV).

Multiple choice

The nucleus of an atom has these two particles.

  1. proton and electron

  2. neutron and electron

  3. neutron and proton

  4. proton and atom
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The nucleus of an atom is composed of protons and neutrons, while electrons orbit the nucleus.

Multiple choice

A neutron has a __________ charge.

  1. negative

  2. positive

  3. large

  4. none of the answers
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A neutron is a subatomic particle that carries no electric charge, meaning it is neutral.

Multiple choice

In which case would an atom be considered neutral ?

  1. it has 3 protons & 4 electrons

  2. it has 4 neutrons & 4 electrons

  3. it has 3 protons & 3 neutrons

  4. it has 3 protons & 3 electrons
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

An atom is neutral when the number of positively charged protons equals the number of negatively charged electrons, resulting in a net charge of zero.

Multiple choice

What particles are found outside the nucleus of an atom?

  1. only protons

  2. only electrons

  3. only neutrons

  4. both electrons & neutrons
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In the standard model of the atom, protons and neutrons are located in the nucleus, while electrons orbit the nucleus in shells or clouds.

Multiple choice

Which subatomic particle has the smallest mass?

  1. Electrons

  2. Protons

  3. Neutrons
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Electrons have an extremely small mass of about 1/1836 amu, which is negligible compared to the mass of protons and neutrons (about 1 amu each). Therefore, electrons contribute almost nothing to the overall mass of an atom.