Ch21

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toc =Guiding Questions 1-33=

= = = Lab: What is the relationship between magnetic field strength and distance from the source? =

Pre-Lab

 * 1) The objective is stated in the title. What is your hypothesis? (Attempt to answer the question, to the best of your knowledge.)
 * 2) As the distance from the source increases, magnetic field strength decreases. Inverse cube relationship.
 * 3) What is the rationale for your hypothesis? (Provide detailed reasoning here. This may take the form of a list of what you already know about the topics, with a summary at the end.)
 * 4) [[image:Screen_shot_2011-11-22_at_12.41.51_PM.png]]My rationale for my hypothesis is based on this equation. B is the magnetic field strength and "d" is the distance. Because "d" is in the denominator, as the distance increases, the right side of the equation will become smaller and B will also become smaller. "d" is also being cubed in the denominator, so the relationship is an inverse cube relationship.


 * 1) How do you think you might test this hypothesis? (What might you measure and how?)
 * 2) I would use a magnetic field sensor to take readings of the magnetic field at various distance from the source.
 * 3) Read the entire procedure through.
 * 4) Design __data table(s)__ in order to record your observations __and__ calculations. Do this in Excel and post this draft on your wiki.

Field Strength (T) || Experimental Magnetic Field Strength (T) || Percent Error(%) ||
 * Distance(m) || Magnetic Moment (A*m^2) || Permeability Constant (Tm/A) || Theoretical Magnetic

=Lab: Magnetic Force on a Wire=

Pre-Lab

 * 1) The objective is stated as a question. What is your hypothesis?
 * 2) There is a direct relationship between magnetic force and magnetic field strength, current, length of conductor, and angle between the field and current. The relationship follows the equation of F = B*I*L*sin(theta). The relationship between magnetic field strength, current, length, and angle is inverse because these factors are on the same side of the equation.
 * 3) How do you think you might test this hypothesis? (What might you measure and how?)
 * We would vary the length of the conductor and then measure the magnetic field strength for each length.
 * 1) Read the entire procedure through.
 * 2) Design __data table(s)__ in order to record your observations __and__ calculations. Do this in Excel (preferable), and post a copy on your wiki.




 * 1) Answer the following questions:
 * 2) How is the direction of the magnetic force oriented with respect to the directions of magnetic field and current which produced it?\
 * 3) It is perpendicular
 * 4) How do changes in the angle between the current and the magnetic field affect the force acting between them?
 * 5) directly affects the force
 * 6) What angle between the current and the magnetic field produces the greatest force?
 * 7) 90 degrees
 * 8) What angle between the current and the magnetic field produces the least force?
 * 9) 0 degrees
 * 10) How is the magnitude of the force of magnetism related to the magnitude of the length of the wire carrying the current?
 * 11) directly related
 * 12) A graph of force vs. current has a trendline with an equation of y = 0.00559x. What is the theoretical magnetic field strength of the magnet used in this experiment if the loop is 4.2-cm long? Show your work.
 * 13) F = BILsin(theta)
 * 14) F/I = BLsin(theta)
 * 15) .00559 = B*.042*sin(90)
 * 16) B = .133T
 * 17) Find the magnetic force on the conducting loop described above, when the current is 0.352-A.
 * 18) F = BILsin(theta)
 * 19) F = .133*.352*.042*sin(90)
 * 20) F = .00197N

=Motor Activity=

Video:

media type="file" key="Movie on 2011-11-29 at 15.29