# What is the phase difference between the motions of two points on the wave

• looi76
In summary, the phase difference between two points on a wave with a frequency of 500Hz and a speed of 340ms^{-1}, 0.17cm apart is 90 degrees.

#### looi76

[SOLVED] What is the phase difference between the motions of two points on the wave..

## Homework Statement

The frequency of a certain wave is $$500Hz$$ and its speed is $$340ms^{-1}$$.What is the phase difference between the motions of two points on the wave $$0.17cm$$ apart?

## Homework Equations

$$x = \frac{d\lambda}{a}$$

$$v = f\lambda$$

## The Attempt at a Solution

$$f = 500Hz \ \ \ v = 340ms^{-1} \ \ \ a = 0.17 \times 10^{-2} cm$$

$$v = f\lambda$$

$$\lambda = \frac{v}{f} = \frac{340}{500} = 0.68m$$

What should I do next?

Last edited:
Two points 0.68cm apart will be out of phase by 360 degrees.

Kurdt said:
Two points 0.68cm apart will be out of phase by 360 degrees.

Two points $\lambda$ apart will be out of phase by 360 deg.

Regards,

Bill

In this case that is 0.68m. Damn I just realized I said cm, but you know what I mean. :tongue:

So, the answer is = 0.68m by 360° ?

No, I won't be. You know the phase difference between points 0.68m apart is 360°, the question asks the phase difference for 0.17m, which happens to be a quarter the quantity of which we do know the phase difference for. Just one more step =]

looi76 said:
So, the answer is = 0.68m by 360° ?

Define the terms in your first relevant equation - one of those terms should be what you solve for to get the answer.

BTW - check what you wrote for "a" (cm?).

Regards,

Bill

looi76 said:
So, the answer is = 0.68m by 360° ?

As GibZ alluded to, I was trying to coax you toward the right answer not just give you the answer outright (since that would be against forum policy).

$$0.68m = 360^o$$
$$0.17m = x$$

$$x = \frac{0.17 \times 360}{0.68}$$

$$x = 90^o$$

So, the phase difference is $$90^o$$ ?

Thats correct.

## What is the phase difference between the motions of two points on the wave?

The phase difference between two points on a wave is the measure of how much one point's motion is ahead or behind the other point's motion. It is usually measured in degrees or radians.

## How is phase difference calculated?

Phase difference can be calculated by finding the difference in the phases of two points on the wave. This can be done by measuring the distance between the two points and dividing it by the wavelength, then multiplying by 360 degrees (or 2π radians).

## What does a phase difference of 0 mean?

A phase difference of 0 means that the two points on the wave are in sync and their motions are perfectly aligned. This is also known as being in phase.

## What does a phase difference of 180 degrees mean?

A phase difference of 180 degrees means that the two points on the wave are completely out of sync and their motions are exactly opposite of each other. This is also known as being in antiphase.

## How does phase difference affect the interference of waves?

Phase difference is a crucial factor in determining the interference of waves. When two waves with the same frequency and amplitude are in phase, they will amplify each other and create a larger wave. However, when they are in antiphase, they will cancel each other out and create a smaller wave.