Question

what is the main difference between mechanical and electromagnetic waves?
mechanical waves only travel through solids, while electromagnetic waves only travel through gases.
mechanical waves are made of electric fields, while electromagnetic waves are made of particles.
mechanical waves require a medium to travel, while electromagnetic waves do not.
mechanical waves are always visible, while electromagnetic waves are always invisible.

Explanation:

Mechanical waves, like sound waves, need a medium (solid, liquid, gas) to travel. Electromagnetic waves, such as light, can travel through a vacuum (no medium). The orange option correctly states this key difference. The green option is wrong as both types can travel through solids and gases (e.g., sound in air - gas, light in glass - solid). The blue option is incorrect because mechanical waves are made of particle - to - particle interactions and electromagnetic waves are composed of electric and magnetic fields. The teal option is wrong as visibility is not the main difference (e.g., some mechanical waves like sound are not visible, and some electromagnetic waves like radio waves are also not visible).

Answer:

Mechanical waves require a medium to travel, while electromagnetic waves do not.