The wavelength of a moving electron-

How fast is an electron moving if it has a wavelength equal to the distance it travels in one second?

The de Broglie wavelength of a particle of mass $1 \ mg$ moving with a velocity of $10 \ m \ s^{-1}$ is $(h=6.63 \times 10^{-34} \ J \ s)$

In the ground state of a hydrogen atom,an electron absorbs $1.5$ times the minimum energy $\left(2.18 \times 10^{-18} \ J\right)$ required to escape from the atom. The wavelength of the emitted electron (in $m$) is $\left(m_e = 9 \times 10^{-31} \ kg\right)$.

The two particles $A$ and $B$ have de Broglie wavelengths $1 \ nm$ and $5 \ nm$ respectively. If the mass of $A$ is four times the mass of $B$,the ratio of kinetic energies of $A$ and $B$ would be

Two particles $A$ and $B$ are in motion. If the wavelength associated with particle $A$ is $5 \times 10^{-8} \ m$,calculate the wavelength (in $\mathring{A}$) associated with particle $B$ if its momentum is half of $A$.