Well, the propagation of light is fundamentally due to oscillation of electric field and magnetic field perpendicularly, which allows the light waves to propagate in the direction perpendicular to both the existing fields, i.e. light waves propagation solely depends on these fields.

But, sound waves are non other than the transference of energy due to disturbance, as well the propagation of sound wave has already been found to be adiabatic in nature, and through the adiabatic equation,...

the symbols used in the story are:

1. house and shops- it symbolizes Aksionov's family and material possessions
2. nightmare-it symbolizes a bad omen.
3. blood-stained knife- it indicates Aksionov's lack of control over his fate.
4. the prison- Aksionov's pain and subsequent mystical transformation are symbolized by the prison.
5. the book(the lives of the saints)- gives an impression of religiosity.