Summary

• Currents produce magnetic fields
• Fields exert forces on currents
• Charged particles in a magnetic field

• Class Quiz
  
  
• Force between parallel wires applet
  Example #1
  
  
• Solenoids
  Example #2
  
  
  

tb 20.8
A vertical wire carries an electrical current straight down. To the east of this wire, the magnetic field points
A. north              B. east
C. south              D. down
Answer







gc6 20.30
Determine the magnitude and direction of the force between two parallel wires 35 m long and 6.0 cm apart, each carrying 25 A in the same direction.
A. 0.0729 N attractive           B. 0.0729 N repulsive
C. 2.92 N attractive              D. 2.92 N repulsive
Answer







gc6 20.49
A 15 cm long solenoid 1.25 cm in diameter is to produce a field of 0.150 T at its center. How much current should the solenoid carry if it has 575 turns of wire?
A. 94.3 A           B. 31.1 A
C. 12.9 A           D. 9.43 A
Answer







 



C. south
Using the right-hand-rule, point your thumb straight down, the same direction as the current. The curled fingers of your right hand would point south on the east side of the wire.












 



A. 0.0729 N attractive













 



B. 31.1 A