List of top Physics Questions on Atoms and Nuclei asked in CBSE CLASS XII

Calculate the mass of an $\alpha$-particle in atomic mass unit (u).
Given: Mass of a normal helium atom = \( 4.002603 \ \text{u} \)
Mass of carbon atom = \( 1.9926 \times 10^{-26} \ \text{kg} \)

Assertion : In Bohr model of hydrogen atom, the angular momentum of an electron in \( n \)th orbit is proportional to the square root of its orbit radius \( r_n \)

Reason (R): According to Bohr model, electron can jump to its nearest orbits only.

The energy of an electron in a hydrogen atom in ground state is -13.6 eV. Its energy in an orbit corresponding to quantum number \( n \) is -0.544 eV. The value of \( n \) is:
Two nuclei with lower binding energy per nucleon form a nucleus with more binding energy per nucleon. (i) What type of nuclear reaction is it?
Show the variation of binding energy per nucleon with mass number. Write the significance of the binding energy curve.
An electron makes a transition from the \( n = 2 \) level to the \( n = 1 \) level in the Bohr model of a hydrogen atom. Its period of revolution:
(a) Define atomic mass unit (u).
(b) Calculate the energy required to separate a deuteron into its constituent parts (a proton and a neutron).
\( m_D = 2.014102 \, u} \)
\( m_H = 1.007825 \, u} \)
\( m_n = 1.008665 \, u} \)
Use the Bohr's first and second postulates to derive an expression for the radius of the nth orbit in a hydrogen atom.
Using Bohr’s postulates, derive the expression for the radius of the \( n \)-th orbit of an electron in a hydrogen atom. Also find the numerical value of Bohr’s radius \( a_0 \).
The carbon isotope \( {}^{12}_6C \) has a nuclear mass of 12.000000 u. Calculate the binding energy of its nucleus.
An alpha particle approaches a gold nucleus in Geiger-Marsden experiment with kinetic energy \( K \). It momentarily stops at a distance \( d \) from the nucleus and reverses its direction. Then \( d \) is proportional to:
Energy levels A, B, and C of an atom correspond to increasing values of energy i.e., \( E_A<E_B<E_C \). Let \( \lambda_1 \), \( \lambda_2 \), and \( \lambda_3 \) be the wavelengths of radiation corresponding to the transitions C to B, B to A, and C to A, respectively. The correct relation between \( \lambda_1 \), \( \lambda_2 \), and \( \lambda_3 \) is:
A transformer has 500 primary turns and 5000 secondary turns. Input is 220V-50Hz. What's the output?
A double-convex lens, with each face having the same radius of curvature \( R \), is made of glass of refractive index \( n \). Its power is:
State any two properties of a nucleus.
The transition of electron that gives rise to the formation of the second spectral line of the Balmer series in the spectrum of hydrogen atom corresponds to: