The kinetic energy of a moving electron is 180 eV, its linear momentum is about: (mass of 1 electron = $9 \times 10^{-31} kg$)
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → $6.6 \times 10^{-24} kg~ms^{-1}$
The kinetic energy is related to momentum (P) and mass (m) by -
$K.E.=\frac{P^2}{2m}$
$⇒P=\sqrt{2mK.E.}$
$=\sqrt{2×(9×10^{-31}kg)(2.88×10^{-17}J)}$
$≃6.6≃10^{-24}kg\,m/s$