Survey

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Survey

Document related concepts

Higgs mechanism wikipedia, lookup

Electric dipole moment wikipedia, lookup

Mathematical formulation of the Standard Model wikipedia, lookup

Maxwell's equations wikipedia, lookup

Electromotive force wikipedia, lookup

Mathematical descriptions of the electromagnetic field wikipedia, lookup

Electromagnetism wikipedia, lookup

Electroactive polymers wikipedia, lookup

Electric charge wikipedia, lookup

Lorentz force wikipedia, lookup

Transcript

Discussion Question 2B P212, Week 2 Electric Field Due to Point Charges Four point charges 2q, q, q, and q are placed at the corners of a rectangle of dimensions a and 3a as shown in the figure. A fifth charge Q is placed at the center of the rectangle. Our task is to 3 q 2 y a x Q ϑ q q compute the electric field at the center of the rectangle, and then determine the force on Q. (a) Each of the 4 charges at the corners contributes to the electric field E at the center of the rectangle. You’ll have to add these contributions by components. First, start by finding the magnitudes of all the electric field contributions you will need to add together. | Eq | = kq/r2 r= | E2q | = 2kq/r2 5 a 2 Did you draw a sketch? Without it this problem is much harder than it needs to be … (b) Without using your calculator, calculate sin(θ), cos(θ), and tan(θ) where θ is the angle defined in the diagram. (Express your answer algebraically.) sinθ = 1/√10 cosθ = 3/√10 tanθ = 1/3 (c) Now compute the x- and y-components of the electric field at the center of the rectangle. Ex = − 6kq 5 10 a 2 Ey = − 2kq 5 10 a 2 (d) What is the total electric field E at the center of the rectangle, given the particular values q = 3 μC and a = 2 cm? G kq 2kq 2 ( 9e9 )( 3e − 6 ) E = = 2 = = 27e6 N/C 2 2 5a 5 ( 0.02 ) a 10 / 2 ( ) (e) Finally, what is the force on the fifth charge Q due to this electric field, given Q = 4 μC? Remember that force is also a vector, and you should give both its x and y components. Fx = − 6(9e9)(3e − 6) ( 4e − 6 ) 6kqQ = = −102.5 N 2 5 10 a 5 10 (0.02) 2 Fy = − 2kqQ = Fx / 3 = −34.2 N 5 10 a 2