Question

Sound cannot travel through which of the following medium?
A. Air
B. Water
C. Iron rod
D. paper

Answer 1

As a first step, read the question and underline the term cannot. Then, one could recall the concept of sound wave propagation and also the related significant points. Now you could go through the options and recall if there is possibility of sound propagation in each of them and hence find the answer.

Complete step-by-step solution:
In the question, we are provided with four options and then are asked to find which among them doesn’t allow the propagation of sound through them.
In order to answer this question, one should recall the concept of sound propagation.
Sound basically is the sequence of pressure waves that propagates through media that are compressible, for example, air or water even in solids. We know that vibration which basically is the to and fro motion of a body causes sound. Vibrating objects can only produce sound. However, not all vibrations are visible. Take the case of a stretched rubber which when pulled and released causes the band to move and vibrate about the centre axis thus producing sound.
Now let us go back to the given options. Three out of the four, namely, air, water and iron rod do propagate sound through them and the velocity of sound propagation through them is also known. But the paper doesn’t allow sound to propagate through them.
Hence, option D is correct.

Note: In the solution it is mentioned that the velocity of sound propagation in three of the options are known. These values are: (a) speed of sound in air is known to be 343m/s. (b) speed of sound in water is known to have the value of 1498m/s. (c) speed of sound in iron rod is found to have the value of 1450m/s.