Dual Nature Flashcards
What is Heisenberg’s Uncertainty Principle?
It is impossible to measure both the position and momentum of a particle at the same time.
This principle highlights the fundamental limits of measuring quantum systems.
What is the formula associated with Heisenberg’s Uncertainty Principle?
Δx * Δp = h (where h = h/2)
Δx is the uncertainty in position and Δp is the uncertainty in momentum.
What does De Broglie’s relation explain?
The wave nature of matter.
It relates a particle’s momentum to its wavelength.
Write down De Broglie’s relation.
λ = h/p (where λ is the de Broglie wavelength and p is momentum)
h is Planck’s constant.
What does Einstein’s photoelectric equation explain?
The photoelectric effect.
It describes the relationship between the energy of incident light and the emission of electrons.
Write down Einstein’s photoelectric equation.
Kmax = hV - φ
Kmax is the maximum kinetic energy of the photoelectron, V is the frequency of incident light, and φ is the work function.
What are examples of photosensitive substances?
Lithium, sodium, potassium, caesium, rubidium.
These metals emit electrons when illuminated by light.
What are the electrons emitted in the photoelectric effect called?
Photoelectrons.
They are emitted from the surface of the metal when illuminated.
What is the photoelectric effect?
When the surface of a metal is illuminated by electromagnetic radiation, electrons are emitted from it.
This phenomenon occurs only with radiation of suitable frequency.
What is the work function?
The minimum energy required by an electron to escape from the surface of a metal.
It is a characteristic property of each metal.
What important fact did Millikan’s experiment establish?
Electric charge is quantised.
Millikan determined the charge of an electron to be e = 1.602 x 10^-19 C.
What are cathode rays?
Streams of electrons emitted from the cathode of a discharge tube.
They are produced when the gas in the tube is subjected to low pressure and a strong electric field.
