Superpostion of Waves

1. Superposition of Waves Quiz LO5
1. What happens to two or more waves when they come together in the same medium?
2. When two waves approach each other in the same medium and are in phase what
happens generally to the amplitude?
3. When two or more waves interfere with each other and are out of phase what happens to
the amplitude?
4. Given that two waves are travelling towards each other with equal speeds and frequencies
and their amplitudes are 0.5 m and 10 cm respectively, what will be the amplitude of the
resultant wave?
5. Given that two waves are travelling towards each other with equal speeds and frequencies
and their amplitudes are 0.5 m and -0.4 m respectively, what will be the amplitude of the
resultant wave?
6. On the following graph, can you tell which is the resultant wave? What are the
amplitudes of all of the other waves present?

2. Courtesy: Desmos, Inc. 2011
Answers:
1. The waves pass right through each other, interfere with each other and then continue on
their own individual paths.
2. They waves are in phase, so they constructively interfere with each other, adding to each
other’s amplitude.
3. The waves now are out of phase, this means that the destructively interfere with each
other, subtracting from each other’s amplitudes.
4. The resultant wave will have an amplitude of 0.6m or 60 cm depending on which
conversion you made.
5. The amplitude would be 0.1 m, recall that the amplitude of the resultant wave is the
algebraic sum of all of the amplitudes present.
6. The green is the resultant, the amplitude of the red wave is 1, the amplitude of the blue
wave is also 1; the amplitude of the green wave is the sum of the red and blue waves’
amplitudes.