This
is
true
Electromagnetic waves travel fastest through vacuum
Remember Dark Energy is repulsive, the more the faster the universe expands (indeed accelerates), so the faster it would cool down and increase its size, not the other way. Now, no one knows what it is. For instance, if Dark Energy would rather be some other geometric effect, it could have a different ending than just if it is a cosmological constant term. So far, though, all experimental data do not favor anything else that is not compatible with just a cosmological constant ... We'll need to wait few years (~10 years) to get to know much better this with missions and ground experiments that are undergoing or planned to be launched.
Medium.
Medium is matter, and electromagnetic waves do not need matter to travel. Just like the sun, its plasma light travels across space to reach us.
Answer:
Explanation:
Given
same charge on both masses
potential Energy due to Magnetic Field =Kinetic Energy of Particle
and we know
Force due to magnetic field will Provide centripetal Force
and B is equal for both particles
thus 
Diagram D. shows the sound waves generated by a siren
that is moving with constant speed to the left.
A sound wave is the sample of disturbance caused by the movement of strength journeying thru a medium because it propagates far away from the supply of the sound. Sound waves are created by using object vibrations and bring strain waves, for example, a ringing cellular phone.
Sound waves fall into three classes: longitudinal waves, mechanical waves, and strain waves. keep studying to find out what qualifies them as such. Longitudinal Sound Waves A longitudinal wave is a wave wherein the movement of the medium's debris is parallel to the course of the energy transport. Sound propagates via air or different mediums as a longitudinal wave, in which the mechanical vibration constituting the wave occurs along the direction of propagation of the wave.
Learn more about sound waves here:-brainly.com/question/1199084
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