Wave Mechanics Beats Question 4
Question: A tuning fork of frequency 100 when sounded together with another tuning fork of unknown frequency produces 2 beats per second. On loading the tuning fork whose frequency is not known and sounded together with a tuning fork of frequency 100 produces one beat, then the frequency of the other tuning fork is
[NCERT 1977]
Options:
A) 102
B) 98
C) 99
D) 101
Show Answer
Answer:
Correct Answer: A
Solution:
Suppose nA = known frequency = 100 Hz, nB =? x = 2 = Beat frequency, which is decreasing after loading (i.e.
x¯) Unknown tuning fork is loaded so nB¯ Hence nA ? nB ¯ = x¯ …
(i) Wrong nB ¯ ? nA = x¯ …
(ii) Correct
Therefore nB = nA + x = 100 + 2 = 102 Hz.
BETA
