94.20: A magnet is dropped through a vertical copper pipe slightly larger than t21nz z5tu /hrbvb :bo-he magnet. Relative to the speed it would fall in air, the mzzr:/vb5h on2 bu-1t bagnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an i n9u8q j-3m2 m(mlcafdnduced current in a conductor bdm aqcm9lum-(3fj n82 y a magnetic field could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/sfib/b -1xpvl oji yp*o8p() q2econd) is equivalent to which one of the followi/lpvp1x )2b(- *of o8yipqbj ing?

  04.34: A square loop is j:g lrz h8w:/iy4 2itzplaced in a uniform magnetic field perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a side and the 4h8ljy/zr:wi:2i g zt magnetic field B has a strength of 2 T. If the loop is rotated through an angle of $90^{\circ}$ in 0.1 second what would be the average (RMS) induced EMF in the loop?

  97.32: A wire moves through a magnetic field directed into the page.mz)-rb p 8;lk0 8qcybi The wire eb 0b;ypl-miq c8) 8kzrxperiences an induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v throug:gc1 -y wcfu5hh a magnetic field and experiences an induced charge separation as shown. What is the direction o1c5wyg: cfhu- f the magnetic field?

  05.33: The figure below shows a bar moving to the right on 0bxmf7( z(:syvlxc 6 ltwo conducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic field be in the area contained withzx7bx0 : fclvs (6lmy(in the conducting rails?

  00.10: When a wire mov.ka azwn8 z56king through a magnetic field has a voltage induced between the wz8z6. aan5 kkwire’s ends, that voltage is
I. directly proportional to the strength of the magnetic field
II. directly proportional to the velocity of the wire
III. directly proportional to the diameter of the wire

  95.30: A 0.20 m long copper rod hj .4d2l0d3o *zu7j 6xctjldj gas constant velocity 0.30 m/s traveling through a uniform magnetic fieldod3jujg*x0l j6 d4z .lcj2 t7d of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its open, 9z fumej7joi-c(oc 7)l8: uid7dvg ling is perpendicular to the circuit containing the two light bulbs as drawn in figure C1. For figures C2 and C3, a shorting wire of negligible resistance is added as shown. Assume that the magnetic field from the solenoid, shown coming out id7c7:m ljo ev,jl u7 c(z )9fgo8-udi of the plane of the page, decreases uniformly in time at the same rate for each circuit. Rank the circuits for the brightness of the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are assum+ i si6xmy0dj8ed to be close to each other), the resistance of the left-hand c+i6 imsjyxd 08ircuit is slowly increased. In which direction does the galvanometer needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very close to the ope6q 8lv h.1;t 6skvtzacning of a solenoid as shown in the diagram. As the magnet is moved away from the soleno q6a8vzshcv6tt1 . ;lkid at constant speed, what is the direction of conventional current through the resistor shown and what is the direction of the force on the magnet because of the induced current?

  09.37: For the figure shown, the variable resistance in the circuit on thex4kbc i0wj, k- left is increased at a constant rate. Whwkci4x,jk-0b at is the direction of the magnetic field at the point P at the center of the left-hand circuit and in what direction is the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very close to the opening of a solenoid as dvx jg0j,9/ myshown in the diagram. As the magnet is moved to the left toward the solenoid, a conventional current through the resistor shown is directed from A to B.g/0x, 9jyvdjm What is the direction of the force on the bar magnet because of the induced current in the solenoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular l( cwnv2za: *yzpcf +k(oops of resistive wire are placed next to each other as in the figure. The circular loop on the left is connected to a constant voltage source V. The resistance of this loop is increasing linearly with time. As the resistance is changing, what is the direction of the magnetic field at point P (the center of the left-hand loop) cwayfv(2npzk* c+:( z and what is the orientation of the conventional current in the right-hand loop (as viewed in the figure from above)?

  11.41: For the figure aktp 79a )t 7fpimwkol9(p1(ishown, the variable resistance of the outer circuit $R_{inner}$ is decreasing at a constant rate. While this is occurring, in which direction is the magnetic field associated with the outer circuit at the point P in the plane of the circuit and in which direction is the conventional current through the resistor $R_{outer}$ in the smaller interior circuit? The two circuits lie on a flat table.

  13.35: For the figure shown, the variable resistanc crnvu:n g310:rvvgjqky90m)e of the innercircuit $R_{inner}$ is increasing at a constant rate. While this isoccurring, in which direction is the magnetic field associated with the inner circuit at the point P in the plane of the circuitand in which direction is the flow of electrons through the resistor labeled $R_{outer}$?

  12.38: A square, conducting wire loop sits in a plane perpendicula8c75bi*n tm,0h .xv rji f8ok,rk bc8xr to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadily increases with time. Which one of the following effects best describes thekr58nj.8,v,xbxi7 f ob imct0c kh*r8 result of this field increase?

  16.47: Two small loops of wire aruu( xfmj;u2 p:e located close to a wire with conventional current directed up the page. A scientist then moves the loops away from the current as shown. ; umujx2:f(up What is the orientation of the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left across a set of frictionless conductiu0fs 26gvsmg-y31hi hng rails as seen in the figure. Throughout the region between the rails, there is a uniform magnetic field directed into the plane of the page. The re-s2vhusfgighm y1 063 sistors labeled X and Y are identical. Which one of the following choices correctly indicates the direction of the conventional current in the resistors and the relation between the magnitude of the currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid xl,vi1twy ;x;4bdpqlx25 z5 4zhav*bpasses through the circuit as shown. The magnetic field of the solenob1;y5hza*,d4;5z px xiqlt x2lv4vwbid, directed into the
plane of the page, is weakening which produces a constant emf of magnitude ξ for a closed loop around the outside of the solenoid. Once equilibrium is established in this circuit, what is the voltage across the switch S?

  15.50 A magnetic field directed intk6i g2qg+pdul58d2 oeo the plane of the page is decreasing in time. A constant emf ξ is produced for the square loop enclosing the field in the figure. The square loop has three identical light bulbs of resistance R in it and an ideal voltmeter connected to the corners through the center of the lokqu2+o5p2 e lgg8id 6dop. What is the magnitude of the voltmeter’s reading?