What current is needed in the solenoid’s wires?

In summary, a researcher needs to perform an experiment in zero magnetic field and has a solenoid with specific dimensions and wire turns. Using Ampere's law, the researcher calculates the current needed in the solenoid's wires to exactly cancel out the Earth's magnetic field. The correct current is 25.5 milliamp with a strength of 5 * 10^-5 Tesla.
  • #1
jlmessick88
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0

Homework Statement


A researcher would like to perform an experiment in zero magnetic field, which means that the field of the Earth must be cancelled. Suppose the experiment is done inside a solenoid of diameter 1.0 m, length 4.0 m, with a total of 5000 turns of wire. The solenoid is oriented to produce a field that opposes and exactly cancels the field of the earth. What current is needed in the solenoid’s wires?


Homework Equations


∑B ∆length = (µ0)I


The Attempt at a Solution


B = 5 * 10^-5 T
length = 4 m
radius = 0.5 m


i = [4*(5*10^-5)]/(5000*2*pie*0.5)
i = 1.27*10^-8

have i done this correctly at all??
 
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  • #2
using Ampere's law the magnetic field ina solenoid will be given by

B= magnetic permeability x current i x number of turns N / length L

and for cancelling Earth's magnetic field, the current needed is

i = B x L / N x magnetic permeability

= 0.4x10^-4 x 4 / 5000x 4 pi x 10^-7 = 2.55 x 10^-2 Amp

= 25.5 milli amp.

Or is this correct??
 
  • #3
That would look correct but I don't know the strength of Earth's magnetic field off-hand
 
  • #4
my book says that the Earth's magnetic field strenght is 5 *10^-5...so would i use that instead of the .4 x 10^-4??
 
  • #5
Yes.
 

1. What is the purpose of a solenoid's wires?

The wires in a solenoid serve as the conductive path for electric current to flow through, creating a magnetic field within the solenoid. This magnetic field is used to control the movement of a plunger or armature, which can be used for various purposes such as opening/closing valves or activating switches.

2. How do you determine the appropriate current for a solenoid's wires?

The required current for a solenoid's wires depends on factors such as the size and number of turns in the solenoid, the material and thickness of the wires, and the desired strength of the magnetic field. It is important to consult the manufacturer's specifications and guidelines to determine the appropriate current for a specific solenoid.

3. Can too much current damage a solenoid's wires?

Yes, applying too much current to a solenoid's wires can cause them to overheat and potentially burn out. This can also damage the insulation on the wires, leading to short circuits or other malfunctions. It is important to use the appropriate current for a solenoid to ensure its safe and proper functioning.

4. How does the direction of current affect the magnetic field in a solenoid?

The direction of current flowing through a solenoid's wires determines the direction of the magnetic field created. Reversing the direction of current will result in a corresponding change in the direction of the magnetic field. This can be useful in controlling the movement of the plunger or armature in a solenoid.

5. Is the current in a solenoid's wires constant or variable?

The current in a solenoid's wires can be either constant or variable, depending on the application. In some cases, a constant current is needed to maintain a steady magnetic field for continuous operation. In other cases, a varying current may be used to control the strength and direction of the magnetic field for specific actions.

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