Question

An explosion takes place on the surface of moon. An astronaut at some distance from the site of explosion will __________.

• A. observe light and hear sound caused by the explosion
• B. observe light but not hear sound caused by the explosion
• C. hear sound but not observe light caused by the explosion
• D. neither hear sound nor observe light caused by the explosion

Answer 1

Answer: (B)

observe light but not hear sound caused by the explosion

Since light is an electromagnetic wave which does not required any medium to propagate. Light waves can travel through vacuum also. Whereas, sound wave, being longitudinal wave, require a material medium to propagate. So sound wave cannot travel through medium. So the astronaut will observe the light of explosion but cannot hear it.