# What happens when 2 light waves meet

### Wave interference - Wikipedia Study the different features of waves with BBC Bitesize KS3 Science. If two waves meet each other in step, they add together and reinforce each other. A laser can also show superposition of light waves if it is shone through two narrow . Interference is what happens when two or more waves come together. Although the waves interfere with each other when they meet, they continue For a pulse going from a light rope to a heavy rope, the reflection occurs as if the end is fixed. time to produce half a wavelength is t = T / 2 = 1 / 2f. In physics, interference is a phenomenon in which two waves superpose to form a resultant File:3D Interference of Laser Light Through 2 Pinholes Animation. webm If a crest of one wave meets a trough of another wave, then the amplitude is Constructive interference occurs when the phase difference between the.

The constructive wave interference occurs naturally. However, we can also create the constructive interference by using two speakers. If we place two speakers side-by-side, point them in the same direction, and play the same frequency, we get a constructive interference.

INTERFERENCE of Light - YOUNG'S DOUBLE SLIT Experiment - explained in HINDI

As we know, sound means the vibrations that travel through the air. Both speaker 1 and speaker 2 pushes the air forwards. Hence, the vibrations travel in the forward direction same direction through the air.

Amplitude means the maximum extent of a vibration from the point of equilibrium. If we stand in front of the two speakers, the vibrations produced by two speakers will be added up in the air. As a result, we hear a sound which is much louder than the individual speakers would produce. In other words, if we stand in front of the two speakers, the amplitudes of the two sound waves are added up. This is nothing but a constructive interference. Destructive wave interference The wave interference is said to be a destructive wave interference if the crest of a wave meets the trough of another wave of the same frequency.

Consider two sound waves traveling in the same medium that are out of phase as shown in the below figure.

### Interference of Waves

When these two sound waves having the same frequency meets each other, the amplitudes of the two sound waves cancels each other. Therefore, the resultant sound wave Z amplitude is zero or it is lower than that of the original wave. As we know, if we place two speakers side-by-side, point them in the same direction, and play the same frequency, we get a constructive interference. Now imagine that we start moving one of the speakers backward, at some point, the two sound waves will become out of phase.

## Interference of Waves

If we stand in front of the two speakers, the speaker 1 one pushes the air in the forward direction and the speaker 2 pulls the air backwards. Hence, the vibrations produced by speaker 1 travels in the forward direction and the vibrations produced by speaker 2 travels in the backward direction.

That means the two vibrations produced by speaker 1 and speaker 2 travels in the opposite directions. This is shown in the diagram below for two downward displaced pulses. In this case, a sine pulse with a maximum displacement of -1 unit negative means a downward displacement interferes with a sine pulse with a maximum displacement of -1 unit.

These two pulses are drawn in red and blue. The resulting shape of the medium is a sine pulse with a maximum displacement of -2 units. Destructive Interference Destructive interference is a type of interference that occurs at any location along the medium where the two interfering waves have a displacement in the opposite direction. This is depicted in the diagram below.

• Wave interference

In the diagram above, the interfering pulses have the same maximum displacement but in opposite directions.

The result is that the two pulses completely destroy each other when they are completely overlapped. At the instant of complete overlap, there is no resulting displacement of the particles of the medium. This "destruction" is not a permanent condition. In fact, to say that the two waves destroy each other can be partially misleading.

When it is said that the two pulses destroy each other, what is meant is that when overlapped, the effect of one of the pulses on the displacement of a given particle of the medium is destroyed or canceled by the effect of the other pulse.

Recall from Lesson 1 that waves transport energy through a medium by means of each individual particle pulling upon its nearest neighbor. When two pulses with opposite displacements i. Once the two pulses pass through each other, there is still an upward displaced pulse and a downward displaced pulse heading in the same direction that they were heading before the interference. Destructive interference leads to only a momentary condition in which the medium's displacement is less than the displacement of the largest-amplitude wave.

The two interfering waves do not need to have equal amplitudes in opposite directions for destructive interference to occur. The resulting displacement of the medium during complete overlap is -1 unit.

This is still destructive interference since the two interfering pulses have opposite displacements. In this case, the destructive nature of the interference does not lead to complete cancellation. Interestingly, the meeting of two waves along a medium does not alter the individual waves or even deviate them from their path. This only becomes an astounding behavior when it is compared to what happens when two billiard balls meet or two football players meet.

Billiard balls might crash and bounce off each other and football players might crash and come to a stop.