Which of the following has the largest de Broglie wavelength (all have equal velocity)?

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 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

If the mass of particle $B$ is four times the mass of particle $A$ and the velocity of particle $A$ is eight times the velocity of particle $B$,then the ratio of the de Broglie wavelength of particle $A$ to particle $B$ will be .......

Two particles of masses $m$ and $2m$ have equal kinetic energies. The de-Broglie wavelengths are in the ratio of

What will be the wavelength of a ball of mass $0.1 \,kg$ moving with a velocity of $10 \,m \,s^{-1}?$