# Electron and conducting plate

1. May 22, 2014

### Tanya Sharma

1. The problem statement, all variables and given/known data

An electron is projected from a distance d and with initial velocity u parallel to a uniformly charged flat conducting plate as shown. It strikes the plate after traveling a distance l along the direction of projection. The surface charge density of the conducting plate is equal to

Ans :dε0mu2/el

2. Relevant equations

3. The attempt at a solution

Electric field of the conducting plate = σ/ε0

Force on the electron in y direction = eσ/ε0

ay = eσ/mε0

l=ut and d=(1/2)ayt2

Solving these ,I get σ = 2dε0mu2/el2 ,but this is incorrect.

I would be grateful if somebody could help me with the problem.

#### Attached Files:

• ###### charge.GIF
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2. May 22, 2014

### ehild

Hi Tania,
It looks correct for me, but do not forget the parentheses.

ehild

3. May 22, 2014

### Tanya Sharma

Hello ehild

Thank you very much :)

4. May 22, 2014

### haruspex

Note that the given answer must be wrong since it has the wrong dimensionality.

5. May 22, 2014

### Tanya Sharma

Okay . Thanks for the input .

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