Quantum Physics Flashcards
All objects emits electromagnetic radiation. What is emitted by cold objects
Waves with low frequencies such as radio waves or microwave
All objects emits electromagnetic radiation. What is emitted by hot objects
Waves with high frequencies such as visible light and ultraviolet radiation
What is a black body?
Idealised body that is able to absorb all electromagnetic radiation which falls on it. A black body can also emit thermal radiation depending on its temperature. The radiation emitted forms a continuous spectrum and is unaffected by the nature of the black body surface. Thus, an object emitting electromagnetic radiation which is determined by its temperature is known as a black body radiator.
Which human body parts acts as a black body
The ear. When rays of light enters ear cavity, it will be reflected many times and at each reflection, part of the ray is absorbed until all of the rays are absorbed.
What happens when an objects temperature increases?
It acts as a black body radiator and emits thermal radiation of all wavelengths.
How is light produced?
Light is an electromagnetic wave which is produced from the vibration of an electric charge. In a hot object, electron vibrate rapidly and randomly in any direction and produce light.
What is quantum of energy?
discrete energy packet and not a continuous energy.
value of quantum energy depends on…..
frequency of its waves. E=hf …… (E=photon energy)
The dispersion of white light by a prism produces…
continuous spectrum consisting of seven visible colours. (there is no separation gap between between each colour in the spectrum)
The line spectrum produced by an excited electron…..
is a series of coloured lines with unique wavelengths and frequencies. Each element produces a spectrum with a series of its own distinctive lines. Therefore, line spectrum is used to identify presence of an element.
What phenomena shows that electromagnetic radiation such as light have wave properties?
Diffraction and Interference
What is the hypothesis stated by Louis de Broglie?
All particles can exhibit wave properties
Relationship between de Broglie wavelength and momentum?
L=h/p (L is lambda). so L=h/mv
What shows object such as marbles have particle properties?
has momentum and kinetic energy
Formula of power for photon
P=nhf=nhc/L
