Answer
When an electron makes transition from a state of higher energy to a state of lower energy it does so by emitting energy in form of radiation in the visible spectrum of light.
Since the basic postulates of the atomic theory is that the energy that the electron possess in it's orbit's takes only discrete values and cannot take any random value thus when an electron makes a transition from a state of higher energy to state of lower energy it will emit radiation with energy equal to difference between the energy levels of the 2 orbit's thus we only observe discrete lines.
Mathematically when an electron makes a transition between states the wavelength of light it releases is given by
where 
is Rydberg constant
is upper energy level
is lower energy level
thus we can see that only discrete wavelength's are released and not continuous wavelength's of light.
It’s d because it’s useful output which would be light over total input
7.5/8
Answer:
a = v²/r
Explanation:
The acceleration of a body moving in a circular path is known as the centripetal acceleration. This is the acceleration of a body that keeps the body within the circular path. It is written in terms of the linear velocity v and the radius of the circle of rotation as shown;
a = v²/r where
v is the linear velocity
r is the radius
a is the centripetal acceleration
Answer:
They can generate potentials spontaneously because they have Unstable Membrane Potentials.
Explanation:
Autorythmic cells or Pacemaker cells are cells that provide Action potentials (electrical impulses) that starts off the cardiac cycle.
N:B This action potential is created spontaneously.
To explain further, the heart originate in specialized cardiac muscle cells, called autorhythmic cells, that can excite themselves and therefore are able to generate an action potential without external stimulation by nerve cells. And this sets the cardiac cycle i
(Pumping of the heart) into motion. (The pace maker potential)
The Autorhythmic cells create an action potential spontaneously
And this is possible because they have an UNSTABLE RESTING POTENTIAL that is continuously depolarizing, while it drifts slowly toward threshold. As Na+ ions enter the cell, the inner surface of the plasma membrane becomes less negative gradually, thus generating the pacemaker potential.
