Answer:
Step-by-step explanation:
On sounding two tuning forks together , we hear beats which is heard at a rate equal to difference of frequencies of tuning forks.
In the present case too , beat is heard .
Frequency of beat heard = 3
The frequency of second tuning fork must be higher by 3 or lower by 3
So the possible frequencies of vibration of unknown tuning fork= 440 +3 or 440 - 3
443 Hz
or , 437 Hz .
443 Or 437 is the answer.