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cloudage

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## Homework Statement

An electron microscope employs a beam of electrons to obtain an image of an object. What energy must be imparted to each electron of the beam to obtain a wavelength of 10.0pm?

## Homework Equations

1. E = hv=hc/lambda

2. lambda = h/(mv)

3. KE = .5mv^2

## The Attempt at a Solution

In this problem I thought you could use the first equation to find the energy with the specific wavelength of 10pm. However, the workbook goes through equations 2 and 3 to first find the velocity and then find the kinetic energy. The answers come out very different, so I must be thinking wrong. Can anyone help me understand this?

Since I am solving for energy, why do I need to go through equations 2 and 3?