JAMB - Physics (1992 - No. 20)
What is the frequency of the sound made by a siren having a disc with 32 holes and making 25 revolution per seconds?
80Hz
600Hz
800Hz
1600Hz
Vysvětlení
No of holes x Revolution
F = NH x NR
= 32 x 25
= 800Hz
F = NH x NR
= 32 x 25
= 800Hz