Uncertainty in electron momentum?

Question

An electron passes through a slit of width 6 times 10-8 m. What is the uncertainty in the electron's momentum component in the direction perpendicular to the slit but in the plane containing the slit?

Lost, any help would be great. Thanks

Answer 1

Use the uncertainty principle --- dp*dx >= h/(2pi)

Let dx = slit width, then

dp = h/(2*pi*dx)

YOu can do the plug and chug.