The wavelength of electrons accelerated from rest through a potential difference of \( 40 \, \text{kV} \) is \( x \times 10^{-12} \, \text{m} \). The value of \( x \) is ____________. (Nearest integer)
Given: Mass of electron \( = 9.1 \times 10^{-31} \, \text{kg} \)
Charge on an electron \( = 1.6 \times 10^{-19} \, \text{C} \)
Plank’s constant \( = 6.63 \times 10^{-34} \, \text{Js} \)
