________________ is the part of a longitudinal wave in which the particles of the medium are closer to one another than they normally are and it is the region of high pressure.

______________________ is the part of a longitudinal wave in which the particles of the medium are farther apart than they normally are and it is the region of low pressure.

When coils are farther apart than normal, __________________________ are observed.

Longitudinal waves can be produced in ______________________.

When coils are closer together than normal, _______________ are observed in spring.

Transverse waves can be produced only in_________________.

Which of the following are correct :

(a) When coils are closer together than normal, compressions (C) are observed in spring.

(b) When coils are farther apart than normal, rarefactions (R) are observed.

Which of the following are correct :

(a) When coils are farther apart than normal, rarefactions (R) are observed.

(b) A long flexible spring which can be compressed or extended easily is called slinky.

Vocal cords occur in ____________________

Which of the following are correct :

(a) The substance through which sound travels is called a medium.

(b) Medium can be solid, liquid or a gas.

(c) Sound wave cannot travel in vaccum.