What is the radius of Bohr's fifth orbit for $B^{+4}$ in $\mathring{A}$ (in $.645$)?

Explain linear and angular momentum.

Energy levels $A, B, C$ of a certain atom correspond to increasing values of energy, $i.e.,$ $E_A < E_B < E_C$. If $\lambda_1, \lambda_2$ and $\lambda_3$ are the wavelengths of radiations corresponding to the transitions $C$ to $B$, $B$ to $A$ and $C$ to $A$ respectively, which of the following statements is correct?

In an orbital,the value of $K.E.$ is equal to:

Which energy level transition among the following will have the least wavelength?

If the Thomson model of the atom was correct,then the result of Rutherford's gold foil experiment would have been: