$A$ $200 \ g$ golf ball is moving with a speed of $5 \ m$ per hour. The associated wavelength is $(h = 6.625 \times 10^{-34} \ J \ s)$.

The velocities of two particles $A$ and $B$ are $0.05 \ ms^{-1}$ and $0.02 \ ms^{-1}$ respectively. The mass of $B$ is five times the mass of $A$. The ratio of their de-Broglie's wavelength is

What is the de Broglie wavelength of an electron in the $n^{th}$ Bohr orbit?

When light of wavelength $248 \, nm$ falls on a metal of threshold energy $3.0 \, eV$,the de-Broglie wavelength of emitted electrons is ............. $\mathring{A}$ (Round off to the Nearest Integer). [Use : $\sqrt{3}=1.73, h =6.63 \times 10^{-34} \, Js, m_e =9.1 \times 10^{-31} \, kg, c =3.0 \times 10^{8} \, ms^{-1}, 1 \, eV =1.6 \times 10^{-19} \, J$]

Which of the following has the lowest de Broglie wavelength $\lambda$?

The de Broglie equation applies to: