Question 445: Waves

Question

A tuning fork $A$ produces 5 beats per second with a tuning fork of frequency 480 Hz . When a little wax is stuck to a prong of fork $A$, the number of beats heard per second becomes 2 . What is the frequency of tuning fork $A$ before the wax is stuck to it ?

Accepted Answer

To determine the initial frequency of tuning fork $ A $, denoted as $ f $, we start by considering the beats produced. A beat frequency of 5 beats per second is observed with another tuning fork of 480 Hz. This implies:
$ f = 480 \pm 5 $
This results in two possible initial frequencies for fork $ A $: 485 Hz or 475 Hz.
Next, when a small amount of wax is added to a prong of fork $ A $, its frequency decreases. Subsequently, the beat frequency changes to 2 beats per second. This reduction in beat frequency is only feasible when the frequency of fork $ A $ initially was the higher of the two possibilities, which is 485 Hz.
Therefore, the original frequency of tuning fork $ A $ before adding the wax was 485 Hz.

Answer

475 Hz

Answer

482 Hz

Answer

478 Hz

Answer

485 Hz

Waves

A tuning fork A produces 5 beats per second with a tuning fork of frequency 480 Hz . When a little wax is stuck to a prong of fork A, the number of beats heard per second becomes 2 . What is the frequency of tuning fork A before the wax is stuck to it ?

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