Ch21-22LevineE

Lab-11/22
Pre Lab Questions 1. The objective is stated in the title. What is your hypothesis? a. This is an inverse relationship, as the distance increases, the magnetic field strength decreases. 2. What is the rationale for your hypothesis? a. The equation provided above proves that as the equation gets divided by a larger distance, the value of magnetic field strength decreases because it is being divided by a larger number. 3. How do you think you might test this hypothesis? a. Measure the distance and //m// and use this to solve for B. 4. Read the entire procedure through. 5. Design a data table in order to record your observations and calculations.

Motor Questions- 11/29
1. How does a galvanometer work? When a current passes through a coil, it experiences a magnetic deflecting torque, which causes it to rotate. This fluctuating motions moves the pointer. The direction of current determines the direction of rotations, and the strength of the current determines the amount of rotation.

2. Define motor and generator. A motor converts electrical energy into mechanical energy. A generator converts mechanical energy into electric energy.

3. A motor is a device which converts electrical energy into mechanical energy (motion). Explain how your motor does so. The battery provides the electrical energy, and when the coiled wire spins, this provides the mechanical energy.

4. Why does the one rotor support have only 1/2 of its insulation sanded off? The coil only wants to receive magnetic force in one direction, so that it continues to rotate in a circle, instead of back and forth. By sanding off the insulation on the wire, we are allowing the wire to experience a magnetic force.

5. How could the motor you built be converted to a generator? Describe carefully what would have to be changed and what the result would be. In order to turn this into a generator, the flow of energy would have to be switched. Some mechanism would have to spin the coil in order to provide mechanical energy, which would in turn cause current to flow through the wires and create electrical energy.

Pre-Lab Questions- 11/30
1. The objective is stated as a question. What is your hypothesis? What is your rationale? How will you test this? The magnetic force is directly related to the magnetic field strength, the length of the conductor, the current, and the angle between the field and the current. I formed this hypothesis based off the equation Fmag=B*I*l*sin(theta). I plan to test our hypothesis by changing one variable at a time, and observing the effect it has on the magnetic force.

2. Read the entire procedure through.

3. Design a data table to record your observations and calculations.

4. Answer the following questions:

a. How is the direction of the magnetic force oriented with respect to the directions of magnetic field and current which produced it? We can find the direction of the magnetic force using the right hand rule. When your thumb points in the direction of current, and your fingers point in the direction of the magnetic field, then your palm points in the direction of the magnetic force.

b. How do changes in the angle between the current and the magnetic field affect the force acting between them? As the angle between the current and the magnetic field increases, so does the force. The closer the force is to 90 degrees, the larger the force is.

c. What angle between the current and the magnetic field produces the greatest force? A 90 degree angle produces the greatest force. When the current and the field are perpendicular, the force is strongest.

d. What angle between the current and magnetic field produces the least force? a 180 degree angle produces the least force. When the current and the field are parallel, the force is zero.

e. How is the magnitude of the force of magnetism related to the magnitude of the length of the wire carrying the current? Based on the equation Fmag=B*I*l*sin(theta), it is apparent that the magnitude of the force has a direct relationship with the magnitude of the length of the wire. As the length of the wire increases, so does the magnetic force.

f. A graph of force vs. current has a trendline with an equation of y=.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.

Fmag=B*I*l*sin(theta) Fmag/I.=B*.042*sin90 .00559=B*.042*sin90
 * B= .1331 T**

g. Find the magnetic force on the conducting loop described above, when the current is .352A.

Fmag=B*I*l*sin(theta) Fmag=.1331*.352*.042*sin90
 * Fmag= .00197 N**

Virtual Lab- 12/6