From Ideas to Implementation - Core Flashcards
In J.J Thomson’s experiment, what was measured?
J.J Thomson measured the charge to mass ratio (q/m) for cathode rays
In what year was J.J Thomson’s experiment?
1897
What was Thomson able to calculate?
- r from the deflection of the beam on the screen when the E field was switched off
- E from the relationship E=v/d
- B from the number of turns in the electromagnet and the current flowing through it
What is a cathode ray tube or discharge tube?
It is a sealed glass tube from which most of the air is removed by vacuum pump. A beam of electrons travels from the cathode to the anode and can be deflected by electrical and/or magnetic fields
What is fluorescence?
Fluorescence is the emission of light from a material when it is exposed to streams of particles or external radiation
What is a cathode ray tube or discharge tube?
It is a sealed glass tube from which most of the air is removed by vacuum pump. A beam of electrons travels from the cathode to the anode and can be deflected by electrical and/or magnetic fields
What is fluorescence?
Fluorescence is the emission of light from a material when it is exposed to streams of particles or external radiation
According to previous theory, what do waves propagate through?
A medium
What was one name that was given to the unproven medium that waves travel through?
The aether
What did Einstein say about the aether?
Einstein simply said that its existence or absence was irrelevant. It could not be detected and made no difference to the passage of light.
