WAV-27

Beat frequency

Two close tones.

Reading speed

GoverningBeat frequency

Governing equation

f_b=|f_1-f_2|

where

f1: f1 (Hz)
f2: f2 (Hz)
fb: Beat frequency (Hz)

Lecture brief

Historical brief

d’Alembert’s wave equation, Snell, the thin-lens maker, Doppler and Bragg interference are the classical optics-and-sound toolkit. The lab is propagation, image and shift. This sheet (WAV-27 — Beat frequency) is the form associated with Beat frequency. Working symbols: $f1$ , $f2$ $\rightarrow$ $fb$ . Two close tones. Pedagogical SI sheet with a live model and a swept parameter.

Purpose

Purpose: compute

fb

from

f1

f2

in Waves & optics via

f_b=|f_1-f_2|

Two close tones. Use it when a real waves & optics question must be answered in SI before a code check.

Live realistic example

In symbols

Live case. Given

f1 = 440.000\,\mathrm{Hz}

f2 = 445.000\,\mathrm{Hz}

, the governing relation

f_b=|f_1-f_2|

yields

fb = 5.000\,\mathrm{Hz}

. One governing identity, SI units, a single sweep on the sheet. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

f1 f1440 Hzf2 f2445 Hz

Outputs

Beat frequency fb5.000 Hz

Reading speed

Watch on YouTube

Free library

Full library

Free PDF / open book

YouTube channels

00:0 / 00:08

Narration of this film

One governing identity, SI units, a single sweep on the sheet.

Two close tones. Pedagogical SI sheet with a live model and a swept parameter.

Reading speed

Watch on YouTube