Nodal Line and Anti-nodal Line
![](https://onlinetuition-app.s3-ap-southeast-1.amazonaws.com/notes/physics/img/Picture65.png)
- An anti-node is a point of maximum amplitude where constructive interference occurs. Whereas a node is point of minimum amplitude where destructive interference occurs.
- The anti-nodal line joins all anti-node points. The nodal line joins all node points.
Formula for Interference
![](https://onlinetuition-app.s3-ap-southeast-1.amazonaws.com/notes/physics/img/Picture66.png)
The distance between two antinode line, x, can be related to the wavelength, λ, by the follwing equation:
![](https://onlinetuition-app.s3-ap-southeast-1.amazonaws.com/notes/physics/img/Waves-02.png)
λ = Wavelength
a = Distance between the two wave sources
x = Distance between two successive anti-node lines or node lines
D = Distance from the wave sources to the plane where x is measured.