Electric Field Video Lessons

Concept

# Problem: A uniform electric field exists in the region between two oppositely charged plane parallel plates. A proton is released from rest at the surface of the positively charged plate and strikes the surface of the opposite plate, 1.20 cm distant from the first, in a time interval of 3.80×10−6 sPart AFind the magnitude of the electric field.Part BFind the speed of the proton when it strikes the negatively charged plate.

###### FREE Expert Solution

The force that a charge experiences when placed at a point is given by:

$\overline{){\mathbf{F}}{\mathbf{=}}{\mathbf{q}}{\mathbf{E}}}$

We also need Newton's second law of motion here, which is expressed as:

$\overline{){\mathbf{\Sigma }}{\mathbf{F}}{\mathbf{=}}{\mathbf{m}}{\mathbf{a}}}$

Comparing the two equations:

$\overline{)\begin{array}{rcl}{\mathbf{qE}}& {\mathbf{=}}& {\mathbf{ma}}\\ {\mathbf{E}}& {\mathbf{=}}& \frac{\mathbf{m}\mathbf{a}}{\mathbf{q}}\end{array}}$

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###### Problem Details

A uniform electric field exists in the region between two oppositely charged plane parallel plates. A proton is released from rest at the surface of the positively charged plate and strikes the surface of the opposite plate, 1.20 cm distant from the first, in a time interval of 3.80×10−6 s

Part A

Find the magnitude of the electric field.

Part B

Find the speed of the proton when it strikes the negatively charged plate.