The transition from the state $n = 4$ to $n = 3$ in a hydrogen-like atom results in ultraviolet radiation. Infrared radiation will be obtained in the transition
$2 \to 1$
$3 \to 2$
$4 \to 2$
$5 \to 4$
The number of completely filled shells for the element ${ }_{16} S ^{32}$ is
What is the percentage of $\alpha -$ particles that have more than $1^o$ scattering in Geiger-Marsden experiment?
In a Geiger-Marsden experiment, what is the distance of closest approach to the nucleus of a $7.7 \;MeV$ $\alpha -$particle before it comes momentarily to rest and reverses its direction?
In third orbit of hydrogen atom, de Broglie wavelength of electron is $\lambda $ then radius of third orbit is