Name _____________________________ PID ________________________________Phy2049 – Physics for Engineers and Scientists IIDr. BindellEXAMINATION #1PROBLEM #1(a) What are the magnitude and direction of the electric field at thecenter of the square of the figure below in terms of q, a and anyother constants that you need. [20](b) Suppose that by magic the positive charges in the upper left andthe lower right of the diagram suddenly went on vacation to thePlanet Mongo. Now what is the Electric Field at the center? [10]1ε0=8. 85×10−12 C2/ Nm2k =9×109 Nm2/ C2e=1 .6×10−19Cme=9. 1×10−31Kgμ0= 4 π ×10−7Tm/ AName _____________________________ PID ________________________________PROBLEM #2 Consider a thin ring of charge of radius a with a totalcharge Q residing on it as shown in an exaggeratedfashion in the figure to the right. Point P is on the axisof the ring a distance x from the plane of the ring.(a) What is the linear charge density along the ring?[10](b) What are the x and y components of the electricfield at point P? [25]2Name _____________________________ PID ________________________________PROBLEM #4The electrons in a particle beam have a kinetic energy K. What are the magnitude and direction of theElectric Field that will stop these electrons in a distance d? [10]3Name _____________________________ PID ________________________________FROM TEXTBOOKWhat is the electric field at a location = <-0.4, -0.9, 0.5> m due to a particle with charge +2 nC located at <0.7, -0.6, 0.9> m?What is the source location?What is the observation location?What is the vector that points from the source location to the observation location?What is | | = r?What is the direction of the electric field , which is given by = /| |?What is the value of 14 π ε0 q| |2Finally, write the electric field as a vector:= N/C4Name _____________________________ PID ________________________________For practice, I left the answers on this sheet. This is against the law so don’t tell. Ignore the red x’s.A thin rod lies on the x-axis with one end at -A and the other end at A, as shown in the diagram. Acharge of -Q is spread uniformly over the surface of the rod. We want to set up an integral to findthe electric field at location ‹ 0, y, 0 › due to the rod. Following the procedure discussed in the textbook, we have cut up the rod into small segments, each of which can be considered as a pointcharge. We have selected a typical piece, shown in red on the diagram.Use the following as necessary: x, y, dx, A, Q. Remember that the rod has charge -Q. (a) In terms of the symbolic quantities given above and on the diagram, what is the charge per unit length of the rod?λ = (b) What is the amount of charge dQ on the small piece of length dx?dQ = (c) What is the vector from source to observation location?= (d) What is the distance from the source to the observation location?d = (e) When we set up an integral to find the electric field at the observation location due to the entire rod, what will be the integration variable?5Name _____________________________ PID ________________________________In the figure,, three charged particles lie on a straight line and are separated by a distance d. Charges q1 and q2 are held fixed. Charge q3 is free to move but happens to be in equilibrium (no net electrostatic force acts on it).Find q1 in terms of q2. ============================================The diagram shows two parallel nonconducting rings arranged with their central axes along a common line. Ring 1 has uniform charge q1 and radius R; ring 2 has uniform charge q2 and the same radius R. The rings are separated by a distance d = 3.00R. The net electric field at point P on the common line, at distance R from ring 1, is zero. What is the ratio
View Full Document
Unlocking...