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Your employer asks you to build a 24-cm long solenoid with an interior field of 4.6 mT. The specifications call for a single layer of wire,
Question
Your employer asks you to build a 24-cm long solenoid with an interior field of 4.6 mT. The specifications call for a single layer of wire, wound with the coils as close together as possible. You have two spools of wire available. Wire with a #18 gauge has a diameter of 1.02 mm and has a maximum current rating of 6 A. Wire with a #26 gauge is 0.41 mm in diameter and can carry up to 1 A.
a. Which wire should you use?
b. What current will you need?
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Physics
5 years
2021-07-27T11:31:17+00:00
2021-07-27T11:31:17+00:00 1 Answers
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Answer:
Explanation:
Formula for magnetic field in a solenoid
B = μ₀ N/ L x I
N is total number of turns , L is length of solenoid , I is current , B is magnetic field , μ₀ is constant equal to 4π x 10⁻⁷
Putting the values for 18 gauge wire
N = length of wire / diameter of wire
N = 24 / .102
= 235.3
B = μ₀ N/ L x I
4.6 x 10⁻³ = 4π x 10⁻⁷ x (235.3 / .24) x I
I = 3.735 A
Putting the values for 26 gauge wire
N = length of wire / diameter of wire
N = 24 / .041
= 585.36
B = μ₀ N/ L x I
4.6 x 10⁻³ = 4π x 10⁻⁷ x (585.36 / .24) x I
I = 1.5 A
a ) So 18 gauge wire will be used
b ) as current required in this case is
3.735 A
In the second case current required is 1.5 A which is beyond its tolerence limit.