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c0der

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## Homework Statement

In the cathode-ray tube, electrons having a mass m

are emitted from a source point S and begin to travel

horizontally with an initial velocity v

_{0}. While passing

between the grid plates a distance l, they are subjected to a

vertical force having a magnitude eV/w, where e is the

charge of an electron, V the applied voltage acting across

the plates, and w the distance between the plates. After

passing clear of the plates, the electrons then travel in

straight lines and strike the screen at A. Determine the

deflection d of the electrons in terms of the dimensions of

the voltage plate and tube. Neglect gravity which causes a

slight vertical deflection when the electron travels from S to

the screen, and the slight deflection between the plates.

See attachment for picture

## Homework Equations

∑F

_{y}= ma

_{y}

v

_{y}= a

_{y}t

## The Attempt at a Solution

By Newton's 2nd Law,

ay = eV/mw from 0 to l

By kinematics t1 = l/v0

t2 = t1 + L/v0 = l/v0 + L/v0

From 0 to l, by kinematics:

y1 = 1/2*eV/mw*(l/v0^2)

(v1)y = eV/mw*l/v0

Hence, from l to L where ay is zero

y2 = d = 1/2*eV/mw*l^2/v0^2 + eV/mw*L/v0

It appears the solution is missing the left term I keep getting, any idea why?

#### Attachments

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