node

(noun)

Point on a wave where there is no displacement.

Related Terms

Examples of node in the following topics:

  • Electric Activity in the Heart

    • The sinoatrial node (also commonly spelled sinuatrial node) is the impulse-generating (pacemaker) tissue located in the right atrium of the heart: i.e., generator of normal sinus rhythm.
    • The sinoatrial node (also commonly spelled sinuatrial node, abbreviated SA node) is the impulse-generating (pacemaker) tissue located in the right atrium of the heart, and thus the generator of normal sinus rhythm.
    • These cells form the atrioventricular node (AV node), which is an area between the atria and ventricles, within the atrial septum.
    • If the AV node also fails, Purkinje fibers are capable of acting as the pacemaker.
    • High magnification micrograph of sinoatrial node tissue and an adjacent nerve fiber.

  • Standing Waves and Resonance

    • Nodes are the points where the string does not move; more generally, nodes are where the wave disturbance is zero in a standing wave.
    • The fixed ends of strings must be nodes, too, because the string cannot move there.

  • The Junction Rule

    • Kirchhoff's junction rule states that at any junction (node) in an electrical circuit, the sum of the currents flowing into that junction is equal to the sum of the currents flowing out of that junction.
    • where n is the total number of branches carrying current towards or away from the node.

  • Pictures of Modes

    • The sand collects on node lines (i.e., places where the displacement is zero).

  • Sound Production: Vibrating String and Air Columns

    • The air movement is constrained at the closed end, and there is no displacement, and this is called the node.
    • The distance from the node to the antinode is 1/4 the length of one wavelength, and equal to the length of the tube, as shown in this equation:$\lambda = 4L$This can also be seen in this figure: The frequency is equal to the speed of sound in the air divided by the wavelength, or:$f=\frac {v_w}{\lambda}=\frac {v_w}{4L}$, where vw is the speed of sound in the air, which we learned how to find in a previous atom.

  • Orbital Maneuvers

    • The maneuver requires a change in the orbital velocity vector (delta-v) at the orbital nodes (i.e., the point at which the initial and desired orbits intersect: the line of orbital nodes is defined by the intersection of the two orbital planes).

  • Standing Waves in Air Columns

    • At the closed end, there is no displacement; this is called a node, and the air is halted.
    • The distance from a node to antinode is 1/4 of a wavelength, and is equal to the length of the tube.

  • Standing Waves on a String

    • The points in a standing wave that appear to remain flat and do not move are called nodes.

  • Reflections

    • The points in a standing wave that appear to remain flat and do not move are called nodes.

  • Statistical Mechanics

    • Let's say that the box has length $lx$ in the x-direction; therefore, $k_xl_x = 2\pi n_x$$k_xl_x = 2\pi n_x$where $n_x$ is an integer so that the radiation field has a node at the edges of the box, so between $k_x$ and $k_x + dk$ there are only $2 dk l_x / (2\pi)$different states.