The de Broglie wavelength of a tennis ball of $60 \ g$ moving with a velocity of $10 \ m/s$ is approximately

If the kinetic energy of an electron of mass $9.0 \times 10^{-31} \ kg$ is $2.0 \times 10^{-25} \ J$,the wavelength of the electron in $nm$ is approximately (in $.3$)

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 one of the following explains light both as a stream of particles and as wave motion?

The mass of a particle is $1 \, mg$ and its velocity is $4.5 \times 10^5 \, cm/s$. What will be the wavelength of this particle? $(h = 6.652 \times 10^{-27} \, erg \cdot s)$.

What accelerating potential must be imparted to a proton beam to give it an effective wavelength of $\lambda = 0.05 \ \mathring{A}$? (Given: $m_p = 1.672 \times 10^{-27} \ kg$,$h = 6.626 \times 10^{-34} \ J \cdot s$,$e = 1.602 \times 10^{-19} \ C$)