An insulated wire of diameter 1.0 mm and negligible resistance is wrapped tightly around a cylindrical core of radius 5.0 cm and length 30 cm to build a solenoid. What is the energy stored in this solenoid when a current I = 0.20 A flows through it? (μ0 = 4π × 10-7 T ∙ m/A)

Respuesta :

Answer:

5.92 x 10⁻⁵ J

Explanation:

[tex]N[/tex]  = Total number of turns

[tex]d[/tex]  = diameter of insulated wire = 1 mm = 0.001 m

[tex]l[/tex]  = length of the cylindrical core = 30 cm = 0.30 m

Length is given as

[tex]l[/tex] = [tex]N[/tex] [tex]d[/tex]

0.30 = [tex]N[/tex] (0.001)

[tex]N[/tex]  = 300

[tex]r[/tex] = radius of the core = 5 cm = 0.05 m

Area is given as

[tex]A[/tex] = πr²

[tex]A[/tex] = (3.14) (0.05)²

[tex]A[/tex] = 0.00785 m²

Inductance of the solenoid is given as

[tex]L = \frac{\mu _{o}N^{2}A}{l}[/tex]

[tex]L = \frac{(12.56\times 10^{-7}))(300)^{2}(0.00785)}{0.30}[/tex]

[tex]L [/tex] = 0.00296

[tex]i [/tex] = current in the solenoid = 0.20 A

Energy stored in the solenoid is given as

[tex]U = (0.5)Li^{2}[/tex]

[tex]U = (0.5)(0.00296)(0.20)^{2}[/tex]

[tex]U [/tex] = 5.92 x 10⁻⁵ J