Question

HELP.
which one is mechanical and electromagnetic.


1. does not require a medium


2. requires a medium

Answer 1

-- Mechanical waves DO require a medium in order to travel from place to place.  (Sound can't travel without some material to travel through on the way.)

-- Electromagnetic waves do NOT need a medium in order to travel from place to place.  (Sunlight reaches us from the Sun without anything to travel through on the way.)