In the diagram below each unit on the horizontal axis is 2.00 cm and each unit o
ID: 2286668 • Letter: I
Question
In the diagram below each unit on the horizontal axis is 2.00 cm and each unit on the vertical axis is 1.00 cm. The equipotential lines in a region of uniform electric field are indicated by the blue lines. (Note that the diagram is not drawn to scale.)
(a) What is the direction of the electric field?
(b) Determine the magnitude of the electric field in this region.
What is the definition of electric field in terms of potential difference and distance? V/m
(c) Determine the shortest distance for which the change in potential is 3 V.
Explanation / Answer
Direction of electric field is from lower potential to heigher potential. so 3rd is showing the direction of electric field.
(Electric field) = -(gradient of potential)
So the magnitude of the electric field is given by
|E| = ?V/d
Where d is the distance between two adjacent lines, and ?V is the difference of potential between two adjacent lines. d is easily obtained by pythagoras' theorem and a consideration of similar triangles (look at the triangle formed at the origin by one line of equipotential and the two axes.) The result is d = 8/?20. So
|E| = 6/(8/?20) = 3.35 V/cm = 335 V/m
The shortest distance for which the change in potential is 3V is d/2 or 8.9 m