Exam 2 Flashcards
cathode ray
How it works: there is a tube that is connected to voltage and inside the tube, the voltage breaks apart atoms to create charged particles. There is also a fluorescent screen placed in the tube to show the path of the cathode rays (glows when an electron hits it). The beam of particles is attracted to the cathode and the anode and the electrons show the beam of fluorescence.
cathode ray and magnet
you can place a magnet to deflect the beam of electrons. The beam is undeflected when there is an equal amount of bending. You can change the electric and magnetic field to get more bending. The amount of bending is used to measure mass to charge ratio of electrons. More magnetic field means more deflection.
A stronger magnet will have more deflection of the cathode ray because a higher mass of a ray will have higher momentum which means it won’t be easily deflected.
Cathode ray and charged electrical plates
variables: charged plates can increase/decrease intensity
regular voltage, the ray is deflected towards the +ve plate
Higher voltage, the ray is deflected more to the +ve plate
Less voltage: less deflection
Cathode ray question 1: which way does a magnetic field move?
from north to south pole (point thumb right, the electron movement is helical like the fingers)
Cathode ray question 2: why does the fluorescence decrease as cathode tube goes on?
the ray is further from the ejection point
Cathode ray question 3: what happens if there are charged plates (+ve) in cathode
the beam would deflect towards the +ve side
discovery of the cathode ray tube>
determined charge to mass ratio of electron
cathode is what charge?
-ve charge
Milkman oil drop experiment
How it works: there is a spray of oil drops. Gravity pulls those oil drops downward. The X-rays then hit the oil particles and cause them to pick up electrons. There are also electrically charged plates that suspend the oil in the air due to the balance of upward electrical and downward gravitational pull and this occurs at the voltage equivalent to electron charge.
milkman oil drop experiment
determined the charge on one electron in culombs
Radioactivity
is the spontaneous emission of high-energy radiation by an atom
Discovery by Ernest rutherford
alpha particles (+vely charged), beta particles (-vely charged) and gamma (Y) rays, which are uncharged
gold foil experiment
How it works: alpha particles are directed at gold foil. The ray passes right through the valence shells of the gold atoms but when it comes to the nucleus, they get deflected or even bounce back since they are repelled.
gold foil experiment discovery
that the nucleus contains a very small and dense positively charged core of atoms
Group 17
halogens
