Given below are two statements:
Statement $I$: Atoms are electrically neutral as they contain equal number of positive and negative charges.
Statement $II$: Atoms of each element are stable and emit their characteristic spectrum.
In the light of the above statements, choose the most appropriate answer from the options given below.
Both Statement $I$ and Statement $II$ are incorrect
Statement I is correct but Statement $II$ is incorrect
Statement $I$ is incorrect but Statement $II$ is correct
Both Statement I and Statement $II$ are correct
An electron is moving round the nucleus of a hydrogen atom in a circular orbit of radius $r$. The Coulomb force $\vec{F}$ between the two is
If in nature there may not be an element for which the principal quantum number $n > 4,$ then the total possible number of elements will be
The first line in the Lyman series has wavelength $\lambda $. The wavlength of the first line in Balmer series is
Hydrogen $(H)$, deuterium $(D)$, singly ionized helium $(He^+)$ and doubly ionized lithium $(Li^{++})$ all have one electron around the nucleus. Consider $n = 2$ to $n = 1$ transition. The wavelengths of emitted radiations are $\lambda_1, \lambda_2 \lambda_3$ and $\lambda_4$ respectively.
In 1911 , the physicist Ernest Rutherford discovered that atoms have a tiny, dense nucleus by shooting positively charged particles at a very thin gold foil. A key physical property which led Rutherford to use gold was that it was