Turning points stuff

Newton’s evidence that light is a particle

Sharp shadows

How are cathode rays produced in a discharge tube

Ionises gas in the tube and electrons emitted from cathode, are accelerated toward the anode

Lenses in an electron microscope (in order)

Condenser

Objective

Projector

What does the condenser lens do

Creates a wide parallel beam of electrons, where the electrons in the centre are undeviated, incident on the sample

What does the objective and projector lens do

Cast the electrons onto a fluorescent screen

Special relativity postulates

Speed of light is invariant in free space

Laws of physics have the same form in all inertial reference frames

In the michelson morey experiment, why was a fringe change expected

Speed of light was expected to be different depending on the earths motion relative to the ether, so rotating the apparatus 90 degrees should change the time in which the seperate light rays arrive, so different phase difference so different interference pattern

De broglies hypothesis

All particles have a wave like nature, with a wavelength h/mv

Black body radiation definition

Electromagnetic radiation with a spectrum of a peak depending on temperature

Quantum tunneling

Electrons have to overcome potential barrier, electrons have insufficient evidence to cross over but a fraction of the electrons move between the sample and tip

Proper time definition

Shortest observable time/ the time elapsed between events measured by a clock in the same reference frame as the object being observed

Why are sharp shadows formed in newtons theory of light

Corpuscles travel in straight lines