10 Lines On My Family In English For Class 6

English for level c2

For comparison we will specify that at usual talk of people in the room intensity of a sound approximately by 106 times exceeds an audibility threshold, and intensity of a sound at a rock concert comes nearer to a pain threshold.

The range of sound vibrations corresponding to change of frequency of fluctuations twice is called as an octave. The violin voice, for example, blocks about three and a half octaves (196-2340 Hz), and piano sounds - more than seven octaves (25 - 4186 Hz).

At control of musical instruments the device called by a tuning fork is often used. It consists of the wooden acoustic resonator and the metal fork fastened to it which is adjusted in a resonance. At blow all system is excited by a hammer on a fork and publishes true musical tone.

Experimental confirmation is given to the second assumption - increase in intensity of fluctuations due to reduction of their duration. The tuning fork which is freely suspended and excited by blow sounds 252 with, attached to a marble board - 115 with, attached to a wooden board - 10 pages. Especially fluctuations amplify if to put a tuning fork to a box resonator with the same own frequency, as at a tuning fork. However duration of fluctuations in this case is even more reduced.

At distribution of a sound in gas atoms and molecules fluctuate along the direction of distribution of a wave. It leads to changes of local density and pressure of p. Sound waves in gas often are called waves of density or waves of pressure.

I. G. Dreyzen and E. Skuchik received expressions for good quality of Q volume resonators. On Dreyzena, intensifying ability of the resonator is defined by the relation of sound pressure in a p2 resonator throat to sound pressure r1 in the falling wave: