The wavelength of an electron in the first orbit of a hydrogen atom is $3.3 \times 10^{-10} \ m$. The kinetic energy of the electron (in $J$) is:
$(h = 6.6 \times 10^{-34} \ Js, m_{e} = 9.0 \times 10^{-31} \ kg)$

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 : $\sqrt{3}=1.73, h =6.63 \times 10^{-34} \, Js, m_e =9.1 \times 10^{-31} \, kg, c =3.0 \times 10^{8} \, ms^{-1}, 1 \, eV =1.6 \times 10^{-19} \, J$]

The wavelength (in $m$) of a particle of mass $11.043 \times 10^{-26} \ kg$ moving with a velocity of $6.0 \times 10^7 \ ms^{-1}$ is $.......$

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

Calculate the mass of a photon with wavelength $3.6 \, \mathring{A}$.

If the kinetic energy of an electron is $2.8 \times 10^{-23} \ J$,then the de Broglie wavelength will be ....... $(m_e = 9.1 \times 10^{-31} \ kg)$.