The wavelength associated with a golf ball weighing $200 \mathrm{g}$ and moving at a speed of $5 \mathrm{m}/\mathrm{h}$ is of the order (Planck constant, $\mathrm{h}=6.626\times {10}^{-34} \mathrm{J} \mathrm{s}$):

Which hydrogen-like species will have the same radius as that of the first Bohr's orbit of the hydrogen atom?

The number of radial nodes in $3\mathrm{s}$ and  $2\mathrm{p}$, respectively, are:

The prominent yellow line in the spectrum of sodium vapour lamp has a wave length of $590 \mathrm{nm}$. What minimum accelerating potential is needed to excite this line in an electron tube containing sodium vapour? $\left(\mathrm{h}=6.63\times {10}^{-34} \mathrm{J}·\mathrm{s}, \mathrm{c}=3\times {10}^8 \mathrm{m} {\mathrm{s}}^{-1}\right)$

Round off your answer to the nearest integer.

If the energy difference between the ground state of an atom and its excited state is $4.4\times {10}^{-19} \mathrm{J}$, The wave length of the photon (in meters) required to produce this transition is $\frac{\mathrm{x}}{2}\times {10}^{-7}\mathrm{m}$. The value of $\mathrm{x}$ is

Round off your answer up to the nearest integer.