BEATS
38.The natural frequency of a tuning fork P is 432Hz, 3beats are produced when tuning fork Pand another tuning fork Q are sounded together.If P is loaded with wax, the no of beats increases to 5 beats/sec The frequency of Q is --------
Frequency of beats:
It is equal to the difference of frequencies of both tuning forks.
Assume that the frequency of tuning fork P is greater than the frequency of tuning fork Q.
Case I: (without loading with wax)
P - Q = 3
Case II: (Tuning fork Q is loaded with wax)
P - Q' = 5
On loading the tuning fork, its frequency reduces.
So, Q' is less than Q.
When Q' is less than Q, then the number of beats (P-Q') should be more than (P-Q).
This is confirmed by increase in the number of beats from 3 to 5 from case I to case II.
From the above confirmation, it can be concluded that our assumption of frequency of tuning fork P is greater than the frequency of tuning fork Q is correct.
So,
P - Q = 3 expression is valid.
Frequency of tuning fork Q:
Q = P - 3
= 432 - 3
= 429 Hz
It is equal to the difference of frequencies of both tuning forks.
Assume that the frequency of tuning fork P is greater than the frequency of tuning fork Q.
Case I: (without loading with wax)
P - Q = 3
Case II: (Tuning fork Q is loaded with wax)
P - Q' = 5
On loading the tuning fork, its frequency reduces.
So, Q' is less than Q.
When Q' is less than Q, then the number of beats (P-Q') should be more than (P-Q).
This is confirmed by increase in the number of beats from 3 to 5 from case I to case II.
From the above confirmation, it can be concluded that our assumption of frequency of tuning fork P is greater than the frequency of tuning fork Q is correct.
So,
P - Q = 3 expression is valid.
Frequency of tuning fork Q:
Q = P - 3
= 432 - 3
= 429 Hz