Your camping buddy has an idea for a light to go inside your tent. He happens to have a powerful (and heavy!) horseshoe magnet that he bought at a surplus store. This magnet creates a
a. Find an expression for the induced current as a function of time if you turn the crank at frequency f. Assume that the semicircle is at its highest point at
b. With what frequency will you have to turn the crank for the maximum current to fully light the bulb? Is this feasible
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Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)
- Review. In Figure P30.42, a uniform magnetic field decreases at a constant rate dB/dt = K, where K is a positive constant. A circular loop of wire of radius a containing a resistance R and a capacitance C is placed with its plane normal to the field. (a) Find the charge Q on the capacitor when it is fully charged. (b) Which plate, upper or lower, is at the higher potential? (c) Discuss the force that causes the separation of charges. Figure P30.42arrow_forwardA circular coil with 200 turns Las a radius of 2.0 cm. (a) What current through tire coil results in a magnetic dipole moment of 3.0 Am2? (b) What is the maximum torque that the coil will experience in a uniform field of strength 5.0102 ? (c) If tire angle between and B is 45°, what is the magnitude of tire torque on the coil? (d) What is the magnetic potential energy of coil for this orientation?arrow_forward(a) What is the speed of a supersonic aircraft with a 17.0-m wingspan, if it experiences a 1.60V Hall voltage between its wing lips when in level flight over the north magnetic pole, where the Earth's field strength is 8.00105T ? (b) Explain why very little current flows as a result of this Hall voltage.arrow_forward
- The square armature coil of an alternating current generator has 200 turns and is 20.0 cm on side. When it rotates at 3600 rpm, its peak output voltage is 120 V. (a) Wliat is the frequency' of the output voltage? (b) What is the strength of the magnetic field in which the coil is turning?arrow_forwardTwo circular loops of wire surround an insulating rod as in Figure P20.53. Loop 1 carries a current I in the clockwise direction when viewed from the left end. If loop 1 moves toward loop 2, which remains stationary, what is the direction of the induced current in loop 2 when viewed from the left end?arrow_forwardA conducting wire shaped in a “U shape” is connected to a 5 ohm light bulb.The 0.8 T external magnetic field is directed into the page as shown. A conducting bar of length 1.2 m is sliding on the conducting wire at 2 m/s to the right. What is the induced emf? Hint: the induced emf is the negative of the change in magnetic flux. The magnetic flux changes because the area of the U shaped wire placed in the magnetic field changes when the conducting wire slides to the right. Induced emf <=> emf = -N ∆Φ/∆t∆Φ =∆(BA)= B ∆A =B ( Af-Ai) Group of answer choices A) 1.92 V B) 0.8 V C) 2.4 V D) 6.8 V Please show how you solved the question and provide explanations. I am struggling in this section of physics, so I greatly appreciate your guidance.arrow_forward
- Consider the arrangement shown in Figure P20.30. Assume R = 6.00 V, ℓ = 1.20 m, and a uniform 2.50-T magnetic field is directed into the page. At what speed should the bar be moved to produce a current of 0.500 A in the resistor?arrow_forwardFigure P19.64 is a setup that can be used to measuremagnetic fields. A rectangular coil of wire contains N turnsand has a width w. The coil is attached to one arm of a balanceand is suspended between the poles of a magnet. The fieldis uniform and perpendicular to the plane of the coil. Thesystem is first balanced when the current in the coil is zero.When the switch is closed and the coil carries a current I, amass m must be added to the right side to balance the system.(a) Find an expression for the magnitude of the magneticfield and determine its direction. (b) Why is the result independentof the vertical dimension of the coil? (c) Supposethe coil has 50 turns and width of 5.0 cm. When the switch is closed, the coil carries a current of 0.30 A, and a mass of 20.0 gmust be added to the right side to balance the system. What isthe magnitude of the magnetic field?arrow_forwardThe bolt of lightning depicted in Figure P20.61 passes 200. mfrom a 100-turn coil oriented as shown. If the current in the lightning bolt falls from 6.02 x 106 A to zero in 10.5 µs, whatis the average voltage induced in the coil? Assume the distanceto the center of the coil determines the average magneticfield at the coil’s position. Treat the lightning bolt as along, vertical wire.arrow_forward
- A long solenoid of radius r = 2.00 cm is wound with3.50 x 103 turns/m and carries a current that changes at therate of 28.5 A/s as in Figure P20.60. What is the magnitude ofthe emf induced in the square conducting loop surroundingthe center of the solenoid?arrow_forwardIn a region of space where the magnetic field of the earth has a magnitude of 80 mT and is directed 30° below the horizontal, a 50-cm length of wire oriented horizontally along an east-west direction is moved horizontally to the south with a speed of 20 m/s. What is the magnitude of the induced potential difference between the ends of this wire? a. 0.40 mV b. 0.35 mV c. 0.69 mV d. 0.45 mV e. 0.30 mVarrow_forwardA long solenoid of radius r = 2.00 cm is wound with 3.50 × 103 turns/m and carries a current that changes at the rate of 28.5 A/s as in Figure P20.60. What is the magnitude of the emf induced in the square conducting loop surrounding the center of the solenoid?arrow_forward
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