Question

calculate d broglie wave length for a beam of electrons whose energy is 45 ev

Answer 1

equation for d broglie wave length :
\[E = hc /\lambda\]
E = energy , ev
h= planck constant = \[6.6 \times10 ^{-34} Js\]
c = speed of light = \[3 \times10^{8} m/s\]
\[\lambda = wave length , m\]
\[1 eV \rightarrow1.062 \times10^{-19} J\]

Answer 2

All the information is there, so it is easy to calculate the wavelength from that.