How could I find the total electric field in this question?

AI Thread Summary
The electric field due to a semicircle is calculated as 2kQ/(πR²). After solving part (a), part (b) becomes straightforward. To find the total electric field, one must also consider the contribution from a point charge at distance 'a' and add the fields vectorially. The calculations provided confirm that the initial findings are correct. The discussion emphasizes the importance of checking directions and combining fields accurately.
Gnall
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Homework Statement
Hello. There is a semicircle charged ring and I found the electric field at the origin. But there is an also extra charge near the origin and the total electric field is zero. I need the charge. I'm trying to solve the 1-b question in the image.
Relevant Equations
Electric field.
The electric field due to the semicircle is 2kQ/pi.Rsquare
Sorry for the bad english.
 

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Gnall said:
The electric field due to the semicircle is 2kQ/pi.Rsquare
Sorry for the bad english.
Having solved a, b looks rather straightforward.
Please post an attempt as per forum rules.
 
I found that. Is that true?
 

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haruspex said:
Having solved a, b looks rather straightforward.
Please post an attempt as per forum rules.

Kq/aSquare=2kQ/piRsquare,
So q=2QaSquare/piRsquare
Is that true?
 
You already found the electric field at centre due to semicircular ring. Find the field due to point charge placed at distance 'a'. Check the directions and add them vectorially (basically just equate them:wink:).

P.S. You got the right answer.
 
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Aryamaan Thakur said:
You already found the electric field at centre due to semicircular ring. Find the field due to point charge placed at distance 'a'. Check the directions and add them vectorially (basically just equate them:wink:).

P.S. You got the right answer.
Thank you so much :)
 

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