Concept explainers
The current in the resistor
Answer to Problem 37P
The net current in
Explanation of Solution
Write the expression for the induced emf.
Here,
Conclusion:
Calculate the emf for the left rod.
Substitute
Here,
Calculate the emf for the sright rod.
Substitute
Here,
Let the current in left loop be
It is given that
Apply Kirchhoff voltage law in left loop.
Apply Kirchhoff voltage law in right loop.
Substitute
Substitute
Further solve for
Substitute
Further solve for
Therefore, current in the left loop is
Substitute
Therefore current in the right loop is
Net current
Substitute
Therefore, the net current in
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Chapter 31 Solutions
PHYSICS:F/SCI...W/MOD..-UPD(LL)W/ACCES
- Figure CQ20.7 shows a slidewire generator with motional cmf 0 when the wire at A slides across the top and bottom rails at constant velocity v0. (a) When the wire reaches B so that the area enclosed by the circuit is doubled, determine the ratio of the new cmf to the original cmf, /0. (b) If the wire's speed is doubled so that v = 2v0 determine the ratio /0. Figure CQ20.7arrow_forwardFigure CQ20.7 shows a slidewire generator with motional cmf 0 when the wire at A slides across the top and bottom rails at constant velocity v0. (a) When the wire reaches B so that the area enclosed by the circuit is doubled, determine the ratio of the new cmf to the original cmf, /0. (b) If the wire's speed is doubled so that v = 2v0 determine the ratio /0. Figure CQ20.7arrow_forwardShow that Equation 32.28 in the text Ls Kirchhoffs loop rule as applied to the circuit in Figure P32.56 with the switch thrown to position b.arrow_forward
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- Figure P23.58 is a graph of the induced emf versus time for a coil of N turns rotating with angular speed ω in a uniform magnetic field directed perpendicular to the coil’s axis of rotation. What If? Copy this sketch (on a larger scale) and on the same set of axes show the graph of emf versus t (a) if the number of turns in the coil is doubled, (b) if instead the angular speed is doubled, and (c) if the angular speed is doubled while the number of turns in the coil is halved. Figure P23.58arrow_forwardFigure P30.39 shows a stationary conductor whose shape is similar to the letter e. The radius of its circular portion is a = 50.0 cm. It is placed in a constant magnetic field of 0.500 T directed out of the page. A straight conducting rod, 50.0 cm long, is pivoted about point O and rotates with a constant angular speed of 2.00 rad/s. (a) Determine the induced emf in the loop POQ. Note that the area of the loop is a2/2. (b) If all the conducting material has a resistance per length of 5.00 /m, what is the induced current in the loop POQ at the instant 0.250 s after point P passes point Q? Figure P30.39arrow_forwardWhen a wire carries an AC current with a known frequency, you can use a Rogowski coil to determine the amplitude Imax of the current without disconnecting the wire to shunt the current through a meter. The Rogowski coil, shown in Figure P23.8, simply clips around the wire. It consists of a toroidal conductor wrapped around a circular return cord. Let n represent the number of turns in the toroid per unit distance along it. Let A represent the cross-sectional area of the toroid. Let I(t) = Imax sin t represent the current to be measured. (a) Show that the amplitude of the emf induced in the Rogowski coil is Emax=0nAImax. (b) Explain why the wire carrying the unknown current need not be at the center of the Rogowski coil and why the coil will not respond to nearby currents that it does not enclose. Figure P23.8arrow_forward
- A circuit consists of a conducting movable bar and a light bulb connected to two conducting rails as shown in Figure OQ23.16. An external magnetic field is directed perpendicular to the plane of the circuit. Which of the following actions will make the bulb light up? More than one statement may be correct. (a) The bar is moved to the left. (b) The bar is moved to the right. (c) The magnitude of the magnetic field is increased. (d) The magnitude of the magnetic field is decreased. (e) The bar is lifted off the rails.arrow_forwardConsider the apparatus shown in Figure P30.32: a conducting bar is moved along two rails connected to an incandescent lightbulb. The whole system is immersed in a magnetic field of magnitude B = 0.400 T perpendicular and into the page. The distance between the horizontal rails is = 0.800 m. The resistance of the lightbulb is R = 48.0 , assumed to be constant. The bar and rails have negligible resistance. The bar is moved toward the right by a constant force of magnitude F = 0.600 N. We wish to find the maximum power delivered to the lightbulb. (a) Find an expression for the current in the lightbulb as a function of B, , R, and v, the speed of the bar. (b) When the maximum power is delivered to the lightbulb, what analysis model properly describes the moving bar? (c) Use the analysis model in part (b) to find a numerical value for the speed v of the bar when the maximum power is being delivered to the lightbulb. (d) Find the current in the lightbulb when maximum power is being delivered to it. (e) Using P = I2R, what is the maximum power delivered to the lightbulb? (f) What is the maximum mechanical input power delivered to the bar by the force F? (g) We have assumed the resistance of the lightbulb is constant. In reality, as the power delivered to the lightbulb increases, the filament temperature increases and the resistance increases. Does the speed found in part (c) change if the resistance increases and all other quantities are held constant? (h) If so, does the speed found in part (c) increase or decrease? If not, explain. (i) With the assumption that the resistance of the lightbulb increases as the current increases, does the power found in part (f) change? (j) If so, is the power found in part (f) larger or smaller? If not, explain. Figure P30.32arrow_forward
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