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## Homework Statement

In a TV tube, an electric potential difference accelerates electrons from a rest position towards a screen. Just before striking the screen, the electrons have a wavelength of 1.0 x10-11m. Find the electric potential difference.[/B]

## Homework Equations

λ = h/mv

E

_{k}= qΔV

## The Attempt at a Solution

[/B]

First, determine the velocity

λ = h/mv

v = h/λm

v = 6.63 x10

^{-34}J / (1.0 x10

^{-11}m)(9.11 x10

^{-31}m/s)

v = 7.28 x10

^{-7}

Now determine the electric potential difference

E

_{k}= qΔV

1/2 mv

^{2}= eΔV

V = 1/2 mv

^{2}/eΔ

V = 1/2 (9.11 x10

^{-31}kg)(7.28 x10

^{-7}m/s)

^{2}/ (1.60 x10

^{-19C) }

V = 1.51 x10

^{-24}

The electric potential difference is 1.51 x10

^{-24}V right before the electron strikes the screen.

I am fairly confident in my methods/answer but I haven't had to calculate the electric potential difference before so I just want to make sure I have the right idea. Any feedback would be great.