Practice Interference in Physics

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

The superposition of two or more waves that overlap in space, producing a combined wave pattern with new amplitudes.

When waves meet, they add up or cancel out at each point depending on whether their crests and troughs align.

Example 1

easy
Two speakers emit identical sound waves in phase. A listener stands equidistant from both speakers. Does the listener hear constructive or destructive interference? What about if one speaker is moved half a wavelength farther away?

Example 2

medium
In a double-slit experiment, light of wavelength 500 \text{ nm} passes through slits 0.2 \text{ mm} apart. A screen is 2 \text{ m} away. What is the spacing between adjacent bright fringes?

Example 3

medium
Two coherent light sources create an interference pattern. The third bright fringe is observed at an angle where the path difference is 3\lambda. If \lambda = 600 \text{ nm}, what is the path difference in meters?

Example 4

hard
In a double-slit experiment, the slit separation is 0.5 \text{ mm} and the screen is 1.5 \text{ m} away. If the fringe spacing is measured to be 1.9 \text{ mm}, what is the wavelength of the light?