CK-12-Physics-Concepts - Intermediate

20.2. Electric Currents and Magnetic Fields http://www.ck12.org

Solution:B=ILF=( 5. 00 A.)(^200 .N 10 m)= 0. (^40) AN·m
Summary

• A moving charged particle creates a magnetic field around it.


• Charge through a wire creates a magnetic field around it, the properties of which can be determined using a
  right hand rule.


• When a moving charged particle moves through another magnetic field, that field will exert a force on the
  moving charged particle that can be expressed usingF=Bqv.


• The relationships between the moving charged particle, magnetic field, and the force exerted can be determined
  using the right hand rule if the particle is positive, or the left hand rule if it is negative.


• When the current is traveling through a magnetic field while inside a wire, the magnetic force is still exerted
  but now it is calculated as the force on the wire rather than on the individual charges in the current, calculated
  usingF=BIL.

Practice

Questions

In this video, a wire is attached to a battery so that a current flows through the wire. The wire and battery combination
is placed in a magnetic field. Use this resource to answer the questions that follow.

http://www.youtube.com/watch?v=yB0qYHkTWJ4

MEDIA

Click image to the left for use the URL below.

URL: http://www.ck12.org/flx/render/embeddedobject/63580

1. What happens to the wire when the current begins to flow?


2. What difference would it make if the magnetic field were stronger?


3. What difference would it make if the battery were 3.0 V instead of 1.5 V?

Review

Questions

1. Find the force on a 115 m long wire at right angles to a 5. 0 × 10 −^5 N/A·mmagnetic field, if the current
   through the wire is 400. A.


2. Find the force on an electron passing through a 0.50 T magnetic field if the velocity of the electron is 4. 0 ×
   106 m/s.


3. A stream of doubly ionized particles(charge= 2 +)moves at a velocity of 3. 0 × 104 m/sperpendicularly to a
   magnetic field of 0.0900 T. What is the magnitude of the force on the particles?


4. A wire 0.50 m long carrying a current of 8.0 A is at right angles to a 1.0 T magnetic field. What force acts on
   the wire?


5. Suppose a magnetic field exists with the north pole at the top of the computer monitor and the south pole at
   the bottom of the monitor screen. If a positively charged particle entered the field moving from your face to
   the other side of the monitor screen, which way would the path of the particle bend?