History of modern laws Flashcards
What is the quantum hypothesis proposed by Max Planck?
Max Planck proposed that heat energy (E) is emitted only in definite amounts called quanta, with the smallest amount of energy given by His equation was E=hf where h = 6.626 x 10-34 J.s (Planck’s constant) f= frequency of radiation
How did Planck explain blackbody radiation?
Planck showed that blackbodies emit more energy at some frequencies and less at others, explaining why they do not radiate equally at all frequencies as classical physics predicted.
What is Einstein’s mass-energy equivalence formula?
Einstein revealed the relationship between energy and mass that eventually lead
to the famous mass-energy equivalence formula E=mc2 (energy equals mass
times the velocity of light squared).
What principle does Einstein’s formula demonstrate?
It demonstrates that mass and energy are interchangeable and all energy has inertia.
How did Bohr modify the atomic model?
Bohr proposed that electrons move in fixed orbits (shells) around the nucleus and each shell has a fixed energy.
What happens when an electron changes energy levels in Bohr’s model?
An electron absorbs energy to move to a higher energy level and releases energy to drop to a lower energy level.
What is the de Broglie wavelength?
It is the wavelength (λ) associated with a particle, given by 𝜆=ℎ|𝑝, where h is Planck’s constant and p is the momentum.
How do classical and modern physics differ in their view of matter and energy?
Classical physics treats matter and energy as separate, while modern physics shows they are interchangeable, as in Einstein’s E=mc2
What is wave-particle duality?
The principle that particles can exhibit wave-like behavior and waves can exhibit particle-like behavior.
How is momentum conserved in physics?
Momentum remains constant in a system if no external forces act on it, as expressed by
mass × velocity=constant
What is Heisenberg’s uncertainty principle?
It states that it is impossible to simultaneously determine the exact position and momentum of a particle.
What does the uncertainty principle imply about measurement?
Measurement errors in position and momentum multiply to at least a constant value, reflecting the limits of accuracy in quantum systems.
