Oh yeah, totally forgot.
So, wavelength = h/mv
Meaning Velocity=h/mλ
So, the correct answers would be:
λ=((2*10^-9)sin(20)) / (1/2) = 1.368*10^-9 m
Vel.=(6.626*10^-34) / ((9.1*10^-31)(1.368*10^-9)) = 5.32*10^5 m/s
Then,
K=(1/2)(9.1*10^-31)(5.32*10^5 m/s)^2 = 1.289*10^-19...
Homework Statement
A beam of electrons is accelerated from rest and then passes through a pair of identical thin slits that are 2 nm apart. You observe the first double-slit interference dark fringes occurring at ±20◦ from the original direction of the beam when viewed on a distant screen.
(A)...