EK Physics Content Review Question #146

[Kouger86]

Q) How much work is required to move a positively charged particle 15cm, if the electric field is 10N/C and the charge on the particle is 8C?

A) 0.8J
B) 8J
C) 12J
D) 1200J

Answer is B

Can someone walk me through this because I keep getting C. I used U=qEd, like they say.


Thanks for the help.

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[robrobbberts]

You are missing the picture that goes with this problem. The question states that the charge particle moves 15cm along the path shown! The path is curved, and so the work done depends only on the distance against the electric field that the particle traveled. the particle only travels 10cm in the horizontal direction (against E), thus you use 10cm instead of 15cm

 

[Kouger86]

Thx for the help. Wow, I didn't even think of looking at the schematic

 

[neil100]

I second rob.

Also, post the entire question with figures next time around. Thanks.

 

[rocketbooster]

You are missing the picture that goes with this problem. The question states that the charge particle moves 15cm along the path shown! The path is curved, and so the work done depends only on the distance against the electric field that the particle traveled. the particle only travels 10cm in the horizontal direction (against E), thus you use 10cm instead of 15cm

hahaha, glad you pointed out that the OP didn't write out the whole question because C was definitely the answer based on what he told us lol

 

[CATSandKILOS]

Can someone explain why we used the formula U=qEd?

 

[azor ahai]

Work = Energy and they give you q, E, and d so that's what you use.