They typically represents different wavelengths of element due to its energy emission in the form of visible light. When an electron of that particular element move from a higher energy level down to a lower energy level, it gives off energy in the form of photon emission. Atom of a certain element has a unique electron arrangement thus it can considered that particular element's spectrum is unique.
The correct is Reverberation. A reverberation is created when a sound or signal is reflected causing a large number of reflections to build up and then decay as the sound is absorbed by the surfaces of objects in the space – which could include furniture, people, and air.
True! All sounds come from some type of vibrating object. Hopefully I helped!
Answer:
Force=7.71KN in the opposite direction
Explanation:
Given the mass of the car(M)=1000Kg
The initial speed of the car(u)=100km/hr
we know that 1km/hr=5/18 m/sec
100km/hr=100*5/18 m/sec=27.77m/sec
the distance travelled before it stops (s)=50m
let the acceleration of the car be a
The final velocity of the car is 0.
we know that 

a=7.712m/
We know that F=Ma
F=1000* 7.712=7712N=7.71KN