# Determine the change in path length

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1. Jan 24, 2016

### Matthew M

1. The problem statement, all variables and given/known data
A ripple tank is setup and a point selected on the second nodal line. determine the change in path length from two wave sources if they are in phase and separated by 2cm and the wave length is 5cm

2. Relevant equations
not really sure of what equations to use?

3. The attempt at a solution
Dont understand what this question means?

2. Jan 25, 2016

### haruspex

If you have quoted the question exactly (and there is no diagram) then I agree it's hard to decipher.
But my guess is they are asking for the difference in path lengths from two sources to a point P, given that:
- the sources are in phase and 2cm apart,
- the wavelength from each source is 5cm
- P is on the second nodal line of the interference pattern

3. Jan 27, 2016

### IAN 25

A node occurs when two waves meet with a wavelength difference of nλ/2 where n is odd. The second nodal line means n = 3. Does this help.