Related Concept Videos

Electrical Current01:10

Electrical Current

Electrical current is defined as the rate at which charge flows. When there is a large current present, such as that used to run a refrigerator, a large amount of charge moves through the wire in a small amount of time. If the current is small, such as that used to operate a handheld calculator, a small amount of charge moves through the circuit over a long period of time. The SI unit for current is the ampere (A), named for the French physicist André-Marie Ampère (1775–1836). An ampere is the...
Magnetic Force On Current-Carrying Wires: Example01:22

Magnetic Force On Current-Carrying Wires: Example

In a magnetic field, moving charges encounter a force. If a wire contains these moving charges, i.e., if the wire is carrying a current, then a force acts on the wire as well. Consider a pair of flexible leads holding a wire that is 40 cm long and 10 g in weight in a horizontal position. The wire is placed in a constant magnetic field of 0.40 T, as shown in Figure 1(a). Determine the magnitude and direction of the current flowing in the wire needed to remove the tension in the supporting leads.
Significance of Displacement Current01:28

Significance of Displacement Current

A displacement current is analogous to a real current in Ampère's law, participating in Ampère's law the same way as the usual conduction current. However, it is produced by a changing electric field. Displacement current is defined in terms of a time-varying electric field, and also has an associated displacement current density. By adding a term accounting for displacement current, Maxwell modified the existing Ampère's law, which is now called generalized Ampère's law.
Muscles of the Forearm that Move the Hand and Fingers01:16

Muscles of the Forearm that Move the Hand and Fingers

The muscles of the forearm that move the wrist, hand, and digits are numerous and diverse. They can be classified into two groups based on their location and function — the anterior and posterior compartment muscles.
Anterior Compartment
The anterior compartment muscles originate from the humerus. They primarily function as flexors and are also known as flexor muscles. They typically insert on the carpals, metacarpals, and phalanges. The superficial layer includes the flexor carpi radialis,...
Spinal Cord Injury ll: Pathophysiology01:14

Spinal Cord Injury ll: Pathophysiology

Spinal cord injury progresses through two interconnected phases: primary injury and secondary injury.Primary InjuryPrimary injury happens at the moment of trauma and involves immediate mechanical damage to the spinal cord.Compression happens when broken vertebrae, herniated discs, or accumulating blood (such as a hematoma) press directly against the spinal cord, distorting its normal shape and function. In cases of contusion, the cord is bruised by a blunt force (like penetrating injuries or...
Degenerative Disc Disease I: Introduction01:27

Degenerative Disc Disease I: Introduction

Degenerative disc disease is a chronic condition in which intervertebral discs gradually lose structure and function. It is not infectious or autoimmune; rather, it results from age-related biochemical and mechanical changes, influenced by genetic, metabolic, and environmental factors.Structure and Function of DiscsThe spine contains 23 intervertebral discs that absorb load, distribute forces, maintain spacing, and allow flexibility. Each disc consists of a nucleus pulposus, a gel-like core...