Using v ∝ √T (in Kelvin), doubling v requires quadrupling T; solving gives T ≈ 1092 K, which is ≈819°C.
902
The echo sounder of a ship transmits a pulse of sound which is reflected back to the ship by a shoal of fish directly below the transmitter. The time between the transmission and reception of the pulse by the ship is 0.1 s. The speed of sound in seawater is 1200 m s^-1. At what depth are the fish?
For sounds of similar frequency (or pitch), louder sounds correspond to larger amplitude of the sound wave.
906
A set of 36 tuning forks is arranged in series of decreasing frequencies. Each fork gives 3 beats with succeeding one. The first fork is an octave of the last. The frequency of the 15th tuning fork from start is
If consecutive forks differ by 3 Hz and f1/2 = f36 = f1 - 35×3, solving gives f1 = 210 Hz; f15 = f1 -14×3 = 210 - 42 = 168 Hz.
907
If a person sees the steam coming out from the chimney of a factory and then after 3 second listens to the sound of whistle, what is the distance of the factory from man? (velocity of sound = 330 m s-1)
|f−240|=4 and |f−252|=8 imply f=244 Hz (difference 4 from 240 and 8 from 252); OCR shows option A marked.
909
A string in a musical instrument is 50 cm long and its fundamental frequency is 800 Hz. If a frequency of 1000 Hz is to be produced, then required length of string is
