In the region shown in the diagram the electric field is uniform, with value = <
ID: 1871934 • Letter: I
Question
In the region shown in the diagram the electric field is uniform, with value = < -460, 230, 0> V/m.
Location A is < 0.1, 0.3, 0 > m; location B is < 0.6, 0.3, 0> m; location C is < 0.6, -0.2, 0> m.
Consider a path from B to A. Which of the following statements are true?
V is a vector quantity, V = < 230, 0, 0> V, V = < -230, 0, 0>, V = < -0.5, 0, 0 > m, V is a scalar quantity, V = 230 V, V = -230 V
What is the change in potential along a path from A to C?
V = volts
An alpha particle (two protons and two neutrons) moves from A to C. What is the change in potential energy of the system (alpha + source charges)? NOTE: a neutron is electrically neutral (no net electrical charge).
U = joules
Explanation / Answer
(A) E = < - 460, 230 , 0 >
BA = A - B = < -0.5 , 0 , 0 >
deltaV = - E.d { dot product}
= - (-460i + 230j + 0 k) . (-0.5i + 0 j + 0 k)
= - [ (-460 x -0.5) + (230 x0) + (0 x 0)]
= - 230 Volt.
V is not a vector quantity.
(B) A to C : CA = <0.5 , -0.5, 0 >
V = - [ ( 0.5 x -460) + (230 x - 0.5) + ( 0 x 0)]
V = 345 Volt ....Ans
change in PE = q deltaV
{ q on alpha = +2e = 2 x 1.6 x 10^-19 C and deltaV = 34 Volt}
change in PE = 1.104 x 10^-16 J