The speed of an electron having a wavelength of $10^{-10} \mathrm{~m}$ is
The speed of an electron having a wavelength of $10^{-10} \mathrm{~m}$ is
$7.25 \times 10^6 \mathrm{~m} / \mathrm{s}$
$5.25 \times 10^6 \mathrm{~m} / \mathrm{s}$
$6.26 \times 10^6 \mathrm{~m} / \mathrm{s}$
$4.24 \times 10^6 \mathrm{~m} / \mathrm{s}$.
Solution
Wavelength $(\lambda)=10^{-10} \mathrm{~m}$.
Velocity of the electron, $v=h / m \lambda$
$=\frac{6.6 \times 10^{-34}}{\left(9.1 \times 10^{-31}\right)\left(10^{-10}\right)}=7.25 \times 10^6 \mathrm{~m} / \mathrm{s} \text {. }$
where $m=$ mass of electron equal to $9.1 \times 10^{-31} \mathrm{~kg}$ and $h$ is Planck constant equal to $6.6 \times 10^{-34} \mathrm{~J}-\mathrm{s}$.