Faraday CT's F-1. A bar magnet is inside an (imaginary) closed surface S. What can you say about the magnetic flux through the surface? SBdA⋅∫GGv is.. A) zero B) positive C) negative D) impossible to tell from the information given F-2. A square loop of area A is in a constant uniform magnetic field. In which situation is the magnetic flux through the loop the smallest? constant, uniform B-field (A) (B)(C) area A edge-onarea A face-onarea A tilted (D) Same flux in all three dAS NF-3. A loop of wire is moving rapidly through a uniform magnetic field as shown. True (A) or False(B): there is a non-zero emf induced in the loop. F-4. A loop of wire is spinning rapidly about a stationary axis in uniform magnetic field as shown. True(A) or False(B): there is a non-zero emf induced in the loop.F-5. The magnetic flux through a loop of wire is shown. At which point is the magnitude of the emf induced in the loop a maximum? flux Φ F-6. A loop of wire is sitting in a uniform, constant magnet field as shown. Suddenly, the loop is bent into a smaller area loop. During the bending of the loop, the induced current in the loop is ... A: zero B: clockwise C: counterclockwise B(in) B(in)time D C B AF-7. A bar magnet is positioned below a horizontal loop of wire with its North pole pointing toward the loop. Then the magnet is pulled down, away from the loop. As viewed from above, is the induced current in the loop clockwise or counterclockwise? F-8. A square loop is rotating in a fixed, external magnetic field into the page. At the instant shown, the loop is out of the plane of the page with left side of the loop above the page and coming out of the page, the right side in going in. The direction of the induced current is ... A: clockwise B: counter-clockwise eyeball N S axis of rotation B(in) A B C) Neither-9. A long, straight wire carrying an increasing current I passes along he induced current in the loop ) zero. ) counter-clockwise ) clockwise. -10. A loop of wire is near a long straight wire which is carrying a re lockwise B: clockwise C: zero. Fa diameter of a wire loop. The straight wire and the loop are in the same plane but are not in electrical contact. Tis: A B C Flarge current I, which is decreasing. The loop and the straight wire ain the same plane and are positioned as shown. The current induced in the loop is A: counter-c I to the right, but decreasing. loop No electrical contact between loop and straight wire. loop I increasingF-11. Two loop of wires labeled A and B are placed near each other as shown. A large current I in loop A is suddenly turned on. This causes an induced current in loop B which causes A: A net replusive force - the two loops repel B: A net attractive force - the two loops attract C: whether the force is attractive or repulsive depends on whether the current in first loop is CW or CCW D: No net force.F-12. A wire loop, moving right, enters a region where there is a constant, uniform magnetic field pointing into the page. B As the loop enters the B-field, the current induced in the loop is ... A: CW B: CCW As the loop enters the B-field, the direction of the net force on the loop is ... A: right → B: ← C: up ↑ D: ↓down E: there is no net forceF-13. The vertical wire shown is moving to the right in a uniform magnetic field which is into the page. There is a current upward, meaning that there is a flow of electrons downward. The fixed positive ions in the wire are moving to the right, along with the wire. The negative conduction electrons are moving to the right and down. What is the direction of the net magnetic force on this segment of the wire? A) Up B) Down C) Left D) Right E) None of these B(in) uniform conventional current I motion of wire and of fixed positive ions electron current motion of conduction electrons in wireF-14. An electric motor consists of a coil, free to turn on an axis, and located in an magnetic field B created by an arrangement of permanent magnets. With the current and field directions as shown, which way will the coil rotate? A: CW axis B B: CCW B C: the coil won't rotate when at this particular orientation I A BF-15. A solenoid has an increasing current causing an increasing B-field in its interior. An end-on view of the solenoid is shown below. A proton is directly below the solenoid. While the current I in the solenoid is increasing, what is the direction of the force on the proton? A B(in) D B E) E-field is zero, so force is zero C proton Hint: What is the direction of the E-field at the position of the proton? Think Lenz's Law. F-16. A long solenoid of radius R contains a uniform magnetic field B which is increasing at a steady rate [B(t) = C t, where C is a constant]. For distances r < R from the center of the solenoid, how does the magnitude of the Electric field depend on r? GGGGEdlddtBda⋅=− ⋅zzej Hint: A: E = zero R B: E ∝ 1/r r BC: E ∝ r D: E ∝ r2 E: E ∝ r3F-17. A rectangular loop is placed in a uniform magnetic field with the plane of the loop perpendicular to the direction of the field. If a current is made to flow through the loop in the sense shown by the arrows, the field exerts on the loop... BA) a net force only B) a net torque only C) a net force and a net torque I D) neither a net torque nor a net force.F-18. A transformer is connected to a battery as shown. The voltage difference across the resistor R is ... A) V N2/N1 B) V N1/N2 C) V D) zero. E) not enough information to answer. F-19. The primary coil of a transformer is connected to a battery, a resistor, and a switch. The secondary coil is connected to an ammeter. When the switch is thrown closed, the ammeter shows.. A) a zero current all the time B) a non-zero current for a brief time when the switch is closed C) a steady non-zero current after the switch is closed V iron core R AV N2 N1 R iron coreF-20. A step-down transformer is attached to an AC voltage source and a resistor as shown. How does the current in the resistor I R compare to the current in the drawn from the AC source Iinput? (With AC circuits, we always use rms values of I and V.) A) I R > I_in B) I R < I_inI_in IR C) I R = I_in D) Depends on the value of Iin F-21. An electrical engineer at a power plant wants to reduce the energy wasted during …
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