Question

Two waves with amplitudes of 75 units and 74 units arrive at a point in a medium simultaneously. If the two waves are out of phase with each other, what is the resultant amplitude of the wave?
a. 74 units

b. 1 unit

c. 75 units

d. m149 units

Answer 1

Answer;

1 unit

Explanation;

• Interference of a wave is the property a wave that occurs when two waves travelling in the same medium meet at a point or superpose at a point in the medium.

• Interference may be constructive or destructive. Constructive occurs when two identical waves travelling in the same medium in phase meet at a point. The resulting wave has twice the amplitude of the individual waves.

• Destructive interference occurs when two waves travelling in the same medium meet and out of phase. The resulting amplitude will be zero if the initial waves are identical, or the difference between the amplitude of the original waves if they are not identical.

• Therefore; If the two waves one with an amplitude 75 units and the other 74 units, are out of phase with each other, the resultant amplitude of the resulting wave will be 1 unit, the difference between the amplitude of the original waves.

Answer 2

If the two waves have the SAME FREQUENCY and are exactly
out of phase (180° apart), then the resultant wave will have the
same frequency and an amplitude of 1 unit.

If the two waves do not have the SAME FREQUENCY, then their
relative phase is meaningless.