# Shared Flashcard Set

## Details

Physics Chapter 38
N/A
14
Physics
12/13/2012

Term
 Electrolysis
Definition
 an electric current through water decomposes the water into hydrogen and oxygen
Term
Definition
 1. Atoms exists. 2.Electric charges are some how associated with atoms. 3.There are two different charges, positive and negative. 4. Electricty is granular rather than a continuos fluid. comes in discrete amounts
Term
Definition
 1. current flows through a low- pressure gas, creating an electric discharge 2. the color of the discharge depends on the type of gas in the tube 3. there is a constant glow around the negative electrode; the cathode glow.
Term
 Plucker's observations of Faraday's gas tube
Definition
 1. As the pressure decreased the colored glow diminished and the cathode glow became more extended 2. when the cathode glow extends to the walls of the tube the glass emits a greenish glow
Term
 Cathode rays
Definition
 Rays that are invisible but cause the glass to glow where they strike it.
Term
 Crooke's Tube
Definition
 1. There is an electric current in a tube in which cathode rays are emitted 2. The rays are deflected by a magnetic field as i they are negative charges. 3. Cathodes made of any metal produce cathode rays 4. The rays can exert forces  on objects and can transfer energy to objects 5. cathode rays are elecrtomagnetic waves
Term
 Thomson's Crossed-Field Experiment
Definition
 electric and magnetic fields were perpendicular to each other  -the magnetic field caused a negatively charged particle to move upward in a circular arc -zero deflection occurs when the magnetic and electrir forces are equal
Term
 A charged particle can pass undeflected through the crossed fields only if it's speed is
Definition
 E   V=---      B
Term
 What did Thomson do to show that all metals emit the same cathode ray?
Definition
 showed that cathode rays can penetrate thin metal foils but atoms cannot.
Term
 Millikan oil-drop Experiment
Definition
 1. A drop will remain suspended between the plates, if the electric field exerts an upward force on a charged drop that exactly balances the downward gravitational force 2. electric charge comes in discrete units and that all charges found in nature are multiples of a fundamental unit of charge e.
Term
 Electron Volt
Definition
 1 elcetron volt is the kinetic energy gained by an electron (or proton) if it accelerates through a potential difference of 1 volt; unit of energy
Term
 Types of spectra
Definition
 1. continuous spectrum: light is emitted at every possible wavelength 2. discrete spectrum: light emitted by one of faraday's gas discharge tubes ; each wavelength is a spectral line
Term
 4 features of a Blackbody Spectra
Definition
 1. all blackbodies at the same temperature emit exactly the same spectrum. the spectrum depends on only an object's temperature, not the material of which it is made. 2. Increase in temperature increasses the radiated intensity at all wavelengths. 3. Increase in temperature causes the peak intensity to shift toward shorter wavelengths. 4. the vissible rainbow is only a small portion of the spectrum
Term
 Emission and Absorption Spectra of a gas
Definition
 Every wavelength absorbed by the gas is also emitted, but not every emitted wavelength is absorbed.
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