Chemistry And Physics Gr.10 June Flashcards
What is a pulse?
A single disturbance through a medium.
What is amplitude?
The maximum disturbance of a particle from its rest position.
What is a transverse pulse?
A vibration causes particles of a medium to move at right angles to the direction of propagation of the pulse.
What is superposition of pulses.
The addition of the disturbances of the two pulses that occupy the same space at the same time.
What is constructive interference?
Two crests/ troughs meet and their amplitudes reinforce each other and the total amplitude is the sum of the individual amplitudes.
What is destructive interference?
One crest and one trough meet and cancel each other out if they have equal amplitudes.
What are transverse waves?
A succession of transverse pulses in the medium travel at right angles to the direction of propagation of the wave.
What term describes the motion of particles in a medium when a wave passes them?
The particles oscillate
What is a wavelength?
The distance between two consecutive points that are in phase.
Measured in metres.
What is a period?
The time it takes for one full cycle.
Measured in seconds.
What is a frequency?
The number of vibration cycles per second.
Measured in Hertz.
Who discovered that atoms contain protons and electrons?
Thomson
Who discovered that electrons move in electron clouds?
Schrödinger
Who discovered that elements are made from atoms?
Dalton
Who discovered that electrons move around nuclei in orbits and energy levels?
Bohr
Who discovered that atoms consist of mostly empty space?
Rutherford
What did Schroedinger discover?
Electrons move in electron clouds.
What did Dalton discover?
Elements are made from atoms
Atoms of the same element are the same
Atoms can form compounds
Atoms can’t be created/ divided destroyed
What did Broglie discover?
Electrons have wave-like properties.
What did Thomson discover?
Atoms contain positive and negative particles.
Negative particles are embedded in a positively charged area
What did Bohr discover?
Electrons move around the nucleus in orbits/shells and energy levels
Electrons have amounts of energy
What did Rutherford discover?
Atoms consist mostly of empty space
Protons exist in the centre of atoms
Electrons around the outside
What experiment did Rutherford use to prove that atoms consist mostly of empty space?
The gold foil experiment.
Why are electrons not used to calculate atomic mass?
Their mass is so small that it’s NEGLIGIBLE.