Atomic Physics JEE Main PYQs, 2020 to 2025

In a hydrogen like ion, the energy difference between the $2^{\text {nd }}$ excitation energy state and ground is 108.8 eV . The atomic number of the ion is:

Given below are two statements :

Statement (I) : The dimensions of Planck's constant and angular momentum are same.

Statement (II) : In Bohr's model electron revolve around the nucleus only in those orbits for which angular momentum is integral multiple of Planck's constant.

In the light of the above statements, choose the most appropriate answer from the options given below :

An electron in the hydrogen atom initially in the fourth excited state makes a transition to $\mathrm{n}^{\text {th }}$ energy state by emitting a photon of energy 2.86 eV . The integer value of n will be__________.

In an alpha particle scattering experiment distance of closest approach for the $\alpha$ particle is $4.5 \times 10^{-14} \mathrm{~m}$. If target nucleus has atomic number 80 , then maximum velocity of $\alpha$-particle is __________ $\times 10^5 \mathrm{~m} / \mathrm{s}$ approximately.

($\frac{1}{4 \pi \epsilon_0}=9 \times 10^9 \mathrm{SI}$ unit, mass of $\alpha$ particle $=6.72 \times 10^{-27} \mathrm{~kg}$)

The waves emitted when a metal target is bombarded with high energy electrons are