Light can travel in vacuum but not sound, because

CONCEPT:

Sound: 

• A sound is a form of energy that produces a sensation of hearing in our ears.
• It is a kind of disturbance that travels through a medium due to repeated vibrations of the particles of the medium about their mean positions.
• The disturbance being handed over from one particle to the next.

Light:

• Light is a form of electromagnetic radiation that can be detected by the human eye.
• When light falls on an object, some part of the light is reflected on our eyes and we are able to see.

EXPLANATION:

• Sound waves are longitudinal waves and light waves are transverse waves. 

• Light can travel in a vacuum because light waves are electromagnetic in nature, which sound waves are not.
• Sound waves require a medium to travel. The speed of sound is faster in solid materials, slower in liquids, and slowest in gases.
• The speed of light in a vacuum is commonly given the symbol c. It is a universal constant that has the value c = 3 x 10⁸ m/second.