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Unformatted text preview: Homework 4 Physics 204, summer 2008 Part 1 1. Read section 10.1 in Physics: The First Science. 2. In a lightning bolt, 16 C of charge flows in a time of 1.5 × 10 −3 s . Assuming that the lightning bolt can be represented as a long, straight line of current, what is the magnitude of the magnetic field at a distance of 20 m from the bolt? 3. Chapter 10 problem 1 4. At New York City, the earth's magnetic field has a vertical component of 5.2 × 10 −5 T that points downward (perpendicular to the ground) and a horizontal component of 1.8 × 10 −5 T that points toward geographic north (parallel to the ground)> What is the magnitude and direction of the magnetic force on a 25.0 m long, straight wire that carries a current of 31 A perpendicularly out of the ground? 5. A square coil of wire containing a single turn is placed in a uniform 0.20 T magnetic field, as the drawing shows. Each side has a length of 0.22 m, and the current in the coil is 12 A. Determine the magnitude and direction of the magnetic force on each of the four sides. 6. In 1996, NASA performed an experiment called the Tethered Satellite experiment. In this experiment a 1.6 × 104 m length of wire was let out by the space shuttle Atlantis to generate a motional EMF. The shuttle had an orbital speed of 7.8 × 103 m s , and the magnitude of the earth's magnetic field at the location of the wire was 4.7 × 10 −5 T . If the wire had moved perpendicular to the earth's magnetic field, what would have been the motional emf generated between the ends of the wire? Part 2 7. Read section 10.3 in Physics: The First Science. 8. The drawing shows that a uniform magnetic field is directed perpendicularly into the plane of the paper and fills the entire region to the left of the y axis. There is no magnetic field to the right of the y axis. A rigid right triangle ABC is made of copper wire. The triangle rotates counterclockwise about the origin at point C. What is the direction (clockwise or counterclockwise) of the induced current when the triangle is crossing each of the following axes? Justify your answers in each case. a. the +y axis b. the ‐x axis c. the ‐y axis d. the +x axis 9. Chapter 10 problem 2 10. Chapter 10 problem 3 11. A solenoid has a cross‐sectional area of 6.2 × 10 −4 m2 , consists of 500 turns per meter, and carries a current of 0.3 A. A 10 turn coil is wrapped tightly around the circumference of the solenoid. The ends of the coil are connected to a 1.5Ω resistor. Suddenly, a switch is opened, and the current in the solenoid dies to zero in a time of 0.12 s. Find the average current induced in the coil. ...
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This note was uploaded on 10/04/2009 for the course PHYS 750:204 taught by Professor Rollino during the Spring '09 term at Rutgers.
- Spring '09