# Gauss' Law: Infinite plane with charge

## Homework Statement

An infinite plane of charge has surface charge density 6.8 µC/m2. How far apart are the equipotential surfaces whose potentials differ by 100 V? In mm

E=σ/(2ε0)

## The Attempt at a Solution

So first I solved for E= 6.8e-6/(2*8.85e-12) = 384170.791

then because ΔV= E *ΔX
so
ΔX=ΔV/E

so then I substituted
ΔX = 100/ 384170.791
ΔX = .0002603

The site says that I've made a power of ten error the answer must be in mm but I'm not sure what Im doing wrong

## Answers and Replies

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gneill
Mentor
ΔX = 100/ 384170.791
ΔX = .0002603

The site says that I've made a power of ten error the answer must be in mm but I'm not sure what Im doing wrong
So far you've expressed your ΔX in meters. What value did you enter for your answer in mm? How many significant figures did you provide?

I entered 2.603 mm

gneill
Mentor
I entered 2.603 mm
Numerically the result looks to be good. How many significant figures do the given data support?

I realized my mistake its supposed to be .2603mm I converted from Meters to millimeters improperly. Thank you.