# Isaac Physics - Aiming an Oscilloscope BeamWatch

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#1
I have been working on this problem for about a week now, and I have completed part A, but cannot get the answer to part B. Would it be possible for someone to walk me through it?

https://isaacphysics.org/questions/a...a-e8e8bcb6d169

For part A, I got u=sqrt((2eV)/me) if that helps.
0
1 month ago
#2
(Original post by ben_dickinson)
I have been working on this problem for about a week now, and I have completed part A, but cannot get the answer to part B. Would it be possible for someone to walk me through it?

https://isaacphysics.org/questions/a...a-e8e8bcb6d169

For part A, I got u=sqrt((2eV)/me) if that helps.
Part B
It’s very similar to throwing a ball horizontally across a vertical gravitational speed ie projectile
Steps
1 find time of flight through the plates in the direction parallel to plates
2 find force on the charge Eq
3 find acceleration in direction of force ie perp to plates. Divide Force by mass
4 using the same time from part one use
SUVAT s = 0.5at-squared where s is the deflection and a is found in step 3
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#3
(Original post by swinroy)
Part B
It’s very similar to throwing a ball horizontally across a vertical gravitational speed ie projectile
Steps
1 find time of flight through the plates in the direction parallel to plates
2 find force on the charge Eq
3 find acceleration in direction of force ie perp to plates. Divide Force by mass
4 using the same time from part one use
SUVAT s = 0.5at-squared where s is the deflection and a is found in step 3
Thank you for your help, spoke to my teacher who said it shouldn't have been set for us
0
3 weeks ago
#4

L == (4*V*h - E*d**(2))/(2*E*d)

1.Derive expression for a between plates
2.Derive the angle leaving the plates using vertical and horizontal suvat
3.Use trig to get expression for h and L (remember the droplet has already travelled some vertical distance, sv between the plates)
4.Use suvat again to get the vertical distance travelled between the plates, sv
5.Substitute in and rearrange for L
Last edited by Fernihough; 3 weeks ago
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