- #1
Nick Jarvis
- 29
- 2
Homework Statement
In a certain region of space, there is a uniform electric field of magnitude
25.0 V m^-1 directed at 30.0 degrees to the direction of the positive x-axis and at 60.0 degrees to the direction of the positive y-axis. (There is no z component of the electric field.) The electric potential at the origin is +150 V. What is the electric potential at the point where x = 5:00 m and y = 12:0 m?[/B]
Homework Equations
I know this is an easy question, but I cannot get my head around it. In the first instance I used:
25.0Vm^-1 = potential difference/distance
Using Pythag, I get the distance to be sqr(5^2 + 12^2) = 13.0m
I know I need to resolve the electric field horizontally and vertically (otherwise I wouldn't have been given the angles). This is exam preparation so I have the answer, but it doesn't give the workings out. If it was all along the horizontal, my answer would be -175V. The answer is NOT this for obvious reasons.
The Attempt at a Solution
[/B]
I tried resolving the electric field along the x and y. 25cos30 = 21.7 and 25sin30 = 12.5
Then using 21.7V^m-1 x 5.0m = 108.5V along the x direction and
12.5V^m-1 x 12.0m = 150.0V, then I tried to using pythag again but my answer does not match with the correct answer. I know I am making it so much more complicated than it needs to be.
Hopefully I have provided the correct info.
Thanks