A fuse in an electric circuit is a wire that is designed to melt, and thereby open the circuit, if the current exceeds a predetermined value. Suppose that the material to be used in a fuse melts when the current density rises to 480 A/cm2. What diameter of cylindrical wire should be used to make a fuse that will limit the current to 0.75 A

Respuesta :

Answer:

The diameter of the  cylindrical wire is 0.0446 cm or 44.6 mm

Explanation:

Given;

current density of the fuse, J = 480 A/cm²

current in the fuse, I = 0.75 A

Current density, J = Current (I) / Area (A)

[tex]Area \ of \ the \ cylindrical \ wire = \frac{Current \ (I)}{Current \ density \ (J)} = \frac{0.75}{480} = 1.5625*10^{-3} \ cm^2[/tex]

[tex]Area \ of \ the \ cylindrical \ wire, A = \frac{\pi d^2}{4} \\\\d^2 =\frac{4*A}{\pi } \\\\d = \sqrt{\frac{4*A}{\pi } } = \sqrt{\frac{4*1.5625*10^{-3}}{\pi } }= 0.0446 \ cm =44.6 \ mm[/tex]

diameter of the wire = 0.0446 cm or 44.6 mm

Therefore, the diameter of cylindrical wire that should be used to make a fuse that will limit the current to 0.75 A, when the current density rises to 480 A/cm²  is 44.6 mm