Power transferred per unit area: $I=P/A$. Its SI unit is watts per square meter.

Wave energy and amplitude

When other relevant conditions are unchanged, wave energy is proportional to amplitude squared.

The rate of energy transfer, given by $P=E/t$; its SI unit is the watt.

Energy transferred at constant intensity

For uniform intensity over area $A$ and time $t$, energy is $E=IAt$.

Constructive interference of identical waves

Identical in-phase waves add their amplitudes; doubling amplitude makes intensity four times greater.

General physicsLesson 11 of 11 in the course Oscillatory Motion and Waves

Wave Energy, Intensity, and Interference

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

Save course

Lesson progress

0 / 5

Your progress is kept in this browser only.Sign up to save it

Summary

Waves carry energy, and the effects they produce depend on how much energy they transfer. This lesson explains how wave amplitude relates to energy and introduces intensity as a measure of power distributed across an area.

The energy carried by a wave is related to its amplitude. A large earthquake can produce greater ground displacement than a small one; a loud sound has a greater pressure amplitude than a soft sound; and a large ocean wave can do more work on a shore than a small wave.

All flashcards

Wave intensity: Power transferred per unit area: $I=P/A$ . Its SI unit is watts per square meter.
Wave energy and amplitude: When other relevant conditions are unchanged, wave energy is proportional to amplitude squared.
Power: The rate of energy transfer, given by $P=E/t$ ; its SI unit is the watt.
Energy transferred at constant intensity: For uniform intensity over area $A$ and time $t$ , energy is $E=IAt$ .
Constructive interference of identical waves: Identical in-phase waves add their amplitudes; doubling amplitude makes intensity four times greater.

Quiz questions

When the same wave power passes through a smaller area, what happens to its intensity?Answer: It increases because the same power is distributed over less area.
Two identical waves arrive in phase at a point. If each has intensity $I$ , what is their combined intensity there?Answer: $4I$
What happens to energy during interference, even when intensity is high at some locations?Answer: Interference redistributes energy across space rather than creating it.
Which equation defines power as a rate of energy transfer?Answer: $P=E/t$
What is the SI unit of intensity?Answer: Watts per square meter

Based on College Physics 2e by Paul Peter Urone, Roger Hinrichs (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

All General physics lessons

General physicsHeat Transfer, Thermal Equilibrium, and the Mechanical Equivalent of Heat5 flashcards · 5 quiz questions · 4 gamesPlay free →General physicsSimple Harmonic Motion: Mass–Spring Period and Oscillator Kinematics5 flashcards · 5 quiz questions · 4 gamesPlay free →General physicsLatent Heat, Heating Curves, and Multistage Phase Changes5 flashcards · 5 quiz questions · 4 gamesPlay free →General physicsSimple Pendulum: Restoring Force, Period, and Measuring Gravity5 flashcards · 5 quiz questions · 4 gamesPlay free →General physicsConvection, Airflow, and Phase-Change Heat Transfer5 flashcards · 5 quiz questions · 4 gamesPlay free →General physicsHooke’s Law, Damping, and Elastic Potential Energy5 flashcards · 5 quiz questions · 4 gamesPlay free →

Summary

All flashcards

Quiz questions

More in General physics