Concept explainers
* A metal rod is connected to a battery through two stiff metal wires that hold the rod horizontally The rod is between the poles of a horseshoe magnet that is sitting on a mass-measuring platform scale, which reads 100 g. Draw the magnetic poles of the magnet and the battery connected to the metal rod so that when you turn the current in the circuit on (a) the reading of the scale supporting the magnet increases; (b) the reading decreases.
Want to see the full answer?
Check out a sample textbook solutionChapter 20 Solutions
College Physics
Additional Science Textbook Solutions
University Physics Volume 2
Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (4th Edition)
College Physics: A Strategic Approach (3rd Edition)
The Cosmic Perspective (8th Edition)
Modern Physics
Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)
- What creates a magnetic field? More than one answer may be correct. (a) a stationary object with electric charge (b) a moving object with electric charge (c) a stationary conductor carrying electric current (d) a difference in electric potential (e) a charged capacitor disconnected from a battery and at rest. Note: In Chapter 24, we will see that a changing electric field also creates a magnetic field.arrow_forwardEddy current are induced currents set up in a piece of metal when it moves through a nonuniform magnetic field. For example, consider the flat metal plate swinging at the end of a bar as a pendulum, as shown in Figure CQ20.9. (a) At position 1, the pendulum is moving from a region where there is no magnetic field into a region where the field B is directed into the paper. Show that at position 1 the direction of the eddy current is counterclockwise. (b) At position 2, the pendulum is moving out of the field into a region of zero field. Show that the direction of the eddy current is clockwise in this case. (c) Use right-hand rule number 2 to show that these eddy currents lead to a magnetic force on the plate directed at shown in the figure. Because the induced eddy current always produces a retarding force when the plate enters or leaves the field, the swinging plate quickly comes to rest. Figure CQ20.9arrow_forwardIf you cut a bar magnet into two pieces, will you end up with one magnet with an isolated north pole and another magnet with an isolated south pole? Explain your answer.arrow_forward
- What creates a magnetic Hold? More than one answer may be correct, (a) a stationary object with electric charge (b) a moving object with electric charge (c) a stationary conductor carrying electric current (d) a difference in electric potential (e) a charged capacitor disconnected from a battery and at rest Note: In Chapter 34, we will see that a changing electric field also creates a magnetic field.arrow_forwardNeurons in our bodies carry weak currents that produce detectable magnetic fields. A technique called magnetoencephalography, or MEG, is used to study electrical activity in the brain using this concept This technique is capable of detecting magnetic fields as weak as 1.0 1015 T. Model the neuron as a long wire carrying a current and find the current it must carry to produce a field of this magnitude at a distance of 4.0 cm from the neuron.arrow_forwardMagnetic field values are often determined by using a device known as a search coil. This technique depends on the measurement of the total charge passing through a coil in a time interval during which the magnetic flux linking the windings changes either because of the coils motion or because of a change in the value of B. (a) Show that as the flux through the coil changes from 1 to 2, the charge transferred through the coil is given by Q = N(2 1)/R, where R is the resistance of the coil and N is the number of turns. (b) As a specific example, calculate B when a total charge of 5.00 104 C passes through a 100-turn coil of resistance 200 and cross-sectional area 40.0 cm2 as it is rotated in a uniform field from a position where the plane of the coil is perpendicular to the field to a position where it is parallel to the field.arrow_forward
- Review A proton is accelerated from rest through a 5.00-V potential difference. a. What is the protons speed after it has been accelerated? b. What is the maximum magnetic field that this proton produces at a point that is 1.00 m from the proton?arrow_forwardCopy Figure P30.6 and sketch the magnetic field lines that result from the bar magnets shown there.arrow_forwardA current I flows around a wire bent into the shape of a square of side a. What is tire magnetic field at the point P that is a distance z above the center of the square (see the accompanying figure)?arrow_forward
- A portion of a long, cylindrical coaxial cable is shown in the accompanying figure. A current I flows down the center conductor, and this current is returned in the outer conductor. Determine the magnetic field in the regions (a)arrow_forwardA laboratory electromagnet produces a magnetic field of magnitude 1.50 T. A proton moves through this field with a speed of 6.00 106 m/s. (a) Find the magnitude of the maximum magnetic force that could he exerted on the proton. (b) What is the magnitude of the maximum acceleration of the proton? (c) Would the field exert the same magnetic force on an electron moving through the field with the same speed? (d) Would the electron experience the same acceleration? Explain.arrow_forward(a) A dc power line for a light-rail system caries 1000 A at an angle of 30.0 to Earth's 5.0105 T field, What is the force on a 100-m section of this line? (b) Discuss practical concerns this presents, if any.arrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage LearningPhysics for Scientists and Engineers, Technology ...PhysicsISBN:9781305116399Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPrinciples of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
- Glencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-HillCollege PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning