(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A uniformly charged insulating rod of length 14.0 cm is bent into the shape of a semicircle. The rod has a total charge of -7.50[itex]\mu[/itex]C. Find (a) the magnitude and (b) the direction of the electric field at O, the center of the semicircle.

2. Relevant equations

d[itex]\overline{E}[/itex] = [itex]\frac{k dq}{r^2}[/itex][itex]\widehat{r}[/itex]

3. The attempt at a solution

This is a continuous charge distribution. The electric field points in the +x direction.

I made dq = [itex]\lambda[/itex]d

and integrated

[itex]\overline{E}[/itex] = [itex]\int[/itex][itex]\frac{k dq}{r^2}[/itex][itex]\widehat{r}[/itex]

from 0 to l, where l is the length of the rod

This is incorrect because r is constant.

R can be found through geometry.

I did not understand how to use cos[itex]\theta[/itex].

I reasoned at the ends of the rod, the angle is 90.

I did not figure out what angle it is.

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# Homework Help: Electric field of a continuously charged semicircle rod at center

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