Lesson: Current Density
In this lesson, we will learn how to describe current density as a vector determining the electric current through an area perpendicular to the current direction.
Sample Question Videos
Worksheet: Current Density • 8 Questions • 3 Videos
The current supplied to an air conditioner unit is 4.00 A. The air conditioner is wired using a 10-gauge (diameter 2.588 mm) wire. The charge density in the wire is electron/m3.
Find the magnitude of current density in the air conditioner’s wiring.
Find the magnitude of the drift velocity in the air conditioner’s wiring.
An electron beam with a radius of 0.90 mm has a measured current . What is the magnitude of the current density of the beam?
A high-energy proton accelerator produces a proton beam with a radius mm. The constant beam current μA. The beam’s charge density protons/m3.
What is the magnitude of the current density of the beam?
What is the magnitude of the drift velocity of the beam?
How much time is required for protons to be emitted by the accelerator?
A wire has a circular cross-section with a radius mm. The current density in the wire is non-uniform and is modeled as , where is a constant with units of . The magnitude of is . What magnitude of current is carried by the inner section of the wire from the axis to ?
A cylindrical wire with radius has a current density , where . What is the current through the wire?
A rod has a square cross section with sides of length 2.0 cm. The current density in the rod , where is measured in meters, as shown in the diagram. Find the current through the face of the rod.
A 20 gauge wire has a cross-sectional area of 0.518 mm2. The current in the wire is modeled as , where is measured in seconds. What is the current density in the wire at the instant ?
If there is one free electron per atom of zinc, find its electron number density. Use a value of 7.13 g/cm3 for the density of zinc.