Look at Lee 14, slide # 11 to answer this question. You may nd slides 7, 8 & 9 useful. The magnitude of torque on the loop (see below} will be minimum when the dashed line [the axis} is _ with respect to the magnetic eld B. {a} Fill in the blank from the choices below. (la) Show why your answer is correct with a calculation. Choose from A. (i) at 45 with respect to B. (ii) This is becase the torque will be _____ (show calculation] B. (i) at 90 with B. (ii) This is because the torque will be ______ [show calculation) C. (i) at 0 with B. (ii) This is because the torque will be _____ (show calculation) D. (i) Cannot be determined. (ii) State why it cannot be determined __ The plane of a circular current loop is oriented at a nonzero angle 6 relative to a magnetic eld parallel to z(see the gure). If the current loop is free to rotate about an axis perpendicular to 2, which of the following is true? (1) The loop will rotate so that the axis of the loop (indicated by the dashed line in the figure) is perpendicular to B. (2) The loop will rotate so that the axis of the loop is parallel to B. (3) Either rotation (axis perpendicular or parallel to B) is possible. Look at Lee 11, Slide #4 and 5 to answer this question. You may also nd Lee 10 slides #19 - 20 useful to ansewr this question. You have three unequal resistors and a battery. (a) How would you connect them so that there is same current passing through each resistor? (b) How would you connect them so that the potential drop across the resistor is equal? Write a sentence or two to answer each question. . When two or more resistors are connected end-to-end they are said to be in series. . From conservation of energy: > Potentials add AV = AV1 + AV2 = IR1 + IR2 = I(R1 + R2) . An equivalent resistance has the same effect on the circuit as the original combination of resistors: AV = IReq . Comparing the above two equations: Req = R1 + R2 A circuit diagram of the Two resistors connected A circuit diagram for the equivalent resistance of in series to a battery. two resistors and battery. the two resistors in series. RI R R =R, +Ry -W AV, AV AV AV bLook at Lec 13, Slide5 - 7 to answer this question. A charge moving at an abitrary angle in a magnetic field will have a component of the velocity that will be constant. (a) Which component is it? (b) What type of path will the charge follow? Your answer: (a) The component Your answer: (b) The type of path is. Consider a particle moving in an external magnetic field so that its velocity is perpendicular The magnetic force F acting on the charge is always directed to the B-field. toward the center of the circle. . Using Right Hand Rule #1, it can be shown that B the particle will move in a circle. The force is X X X X X always directed toward the center of the circular path. X + X X The magnetic force causes a centripetal acceleration, changing the direction of the X velocity of the particle. F . Equating the magnetic and centripetal forces: X X X X X X X