What will be the de-Broglie wavelength of an electron moving with a velocity of $1.2 \times 10^5 \ m \ s^{-1}$?

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

What is the mass of a particle with a wavelength of $3.313 \mathring{A}$ moving with a speed of $2.0 \times 10^8 \ m \ s^{-1}$?

The wavelength of a microscopic particle of mass $9.1 \times 10^{-31} \ kg$ is $182 \ nm$. Its kinetic energy in $J$ is: $(h = 6.625 \times 10^{-34} \ J \ s)$

The de Broglie wavelength is given as $1 \, \mathring{A}$ and the value of $h$ is $6.6252 \times 10^{-27} \, \text{erg} \cdot \text{s}$. What will be the momentum of the particle (in $\text{g} \cdot \text{cm/s}$)?

The de Broglie wavelength associated with a material particle is ......