Flux density and force

In summary, the task is to find the magnitude and direction of the force acting on each kilometer of a power line running along the Earth's equator with a magnetic flux density of 50*10-6T and a current of 500A flowing from west to east. The equation F = ILB\sin(\theta) can be used to solve this problem, and the direction of the force can be determined using Fleming's left hand rule.
  • #1
samblue
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Homework Statement



A power line runs along the Earth's equator where the magnetic flux density, B, points from south to north and has a strength of 50*10-6T. The current in the line is 500A flowing from west to east. Find the magnitude and the direction of the fore acting on eath kilometer of the power line.

Homework Equations



F=qvBsintheta

diection is V cross B.

The Attempt at a Solution



I think I have to use the above equations, however i am unsure how to get the 500A cunnent into this? Is there a relationship linkng v and I? Also although i know how to do a cross product i am unsure how you present the direction, I know you have to use the right hand rule but how do you express this in the exam?

Thanks
 
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  • #2
I think it would be better to use [itex] F = ILB\sin(\theta)[/itex]. To find the direction of the force you need to use Fleming's left hand rule. Your thumb is the direction of the force, your index finger the field and your middle finger the current.

http://hyperphysics.phy-astr.gsu.edu/Hbase/magnetic/forwir2.html
 
  • #3
for the question! To find the force acting on each kilometer of the power line, we first need to calculate the velocity of the charges (electrons) in the power line. This can be done using the relationship V=IR, where I is the current (500A) and R is the resistance of the power line. We can assume a typical resistance of 0.01 ohms per kilometer, so the velocity of the electrons in the power line would be V=500*0.01=5 m/s.

Now, using the equation F=qvBsinθ, we can calculate the magnitude of the force acting on each kilometer of the power line. Plugging in the values, we get F=(500*5*50*10^-6*sin90°)=0.125 N.

To determine the direction of the force, we can use the right hand rule. If we point our right thumb in the direction of the current (from west to east), our fingers will curl in the direction of the magnetic field (from south to north). This means that the force will be directed upwards, perpendicular to both the current and the magnetic field.

In summary, the magnitude of the force acting on each kilometer of the power line is 0.125 N, and the direction of the force is upwards.
 

1. What is flux density?

Flux density, also known as magnetic induction, is a measure of the strength of a magnetic field at a specific point in space. It is typically measured in units of tesla (T) or gauss (G).

2. How is flux density related to magnetic force?

Flux density is directly proportional to the force exerted by a magnetic field on a charged particle. This means that a higher flux density will result in a stronger magnetic force on a particle.

3. What factors affect flux density?

The strength of a magnetic field, the distance from the source of the field, and the material through which the field is passing can all affect flux density. Additionally, the direction and orientation of the magnetic field can also impact flux density.

4. How is flux density measured?

Flux density is typically measured using a device called a magnetometer, which can detect and measure the strength of a magnetic field. The unit of measurement for flux density is tesla (T) or gauss (G).

5. What are some real-world applications of flux density and force?

Flux density and force have numerous real-world applications, such as in the design and operation of electric motors, generators, and transformers. They are also important in medical imaging techniques such as MRI, and in scientific research involving particle accelerators and plasma physics.

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