1143 Questions & Blanks Flashcards
Four properties of cathode rays as demonstrated by J.J.Thomson
They travel in straight lines.
They consist of solid particles.
They carry a negative charge.
Their particles are far smaller than a single atom.
Contrast the wave properties of x-ray to ultraviolet
higher frequency
shorter wave length
higher energy
greater penetrating power
gamma ray
high speed electromagnetic wave emitted from the nucleus of a radioactive element
penetrating power of a gamma particle
greater than alpha or beta
cosmic rays
high-speed charged particles, mostly protons, that strike Earth’s atmosphere from outer space
precaution with x-rays
limit time of exposure
Geiger counter clicks
a radioactive ray produces an ionized path in the gas which completes the circuit
superheated liquid
one that has been heated above its boiling point without causing boiling to take place
How does radiation damage living tissue?
the rays leave unstable atoms and charged particles which attach themselves to neighboring molecules to produce substances that are foreign to cells
What is a model?
a concept that briefly expresses a complex idea
The planetary model of the atom as developed by Ernest Rutherford’s work
includes a heavy, positively charged nucleus and light, negatively charged electrons orbiting at relatively great distances
the nucleus of an atom
a heavy, positively charged central core
alpha particles that traveled through gold foil without changing direction____
struck only electrons. Their mass and velocity allowed them to pass through with their direction unhindered
alpha particles that traveled through gold foil but were bent off course _____
passed close enough to an atom’s positively charged nucleus to be deflected by it
alpha particles that bounced straight back from the gold foil________
struck the nucleus’ dead center
How does the spectroscope help to identify substances objectively?
Each element has its own unique spectral characteristics that identify it exactly. The spectroscope uses these characteristics
The photoelectric effect
the emission of electrons caused by light falling upon the surface of certain metals
Property of light that determines the number of photons
frequency of light
Property of light that determines the energy levels
brightness of light
According to Dr. Einstein’s theory, why do photons of red light not produce the photoelectric effect?
they do not have enough energy to free electrons from most metals
Five new ideas and discoveries made in physics between 1895 and 1905
discovery of the electron, x-rays, and radioactive elements
development of the quantum theory
explanation of the photoelectric effect
Difference between modern and classical physics
Modern physics takes the quantum theory into account. Classical does not.
Properties of standard incandescent light
waves out of phase
differing frequencies
direction follows inverse square law
Properties of laser light
waves in phase
same frequency
waves travel in the same direction
The number of electrons in each atom and their ________ determine an element’s chemical properties
Placement in orbitals
What are isotopes?
Same number of protons, but different number of neutrons
Define radioactivity
The emission of particles or rays from the nucleus of the atom
Radioactive decay can make what three fundamental changes in atoms
Change in atomic number
Change in atomic mass
Change in energy content
What is half-life?
Amount of time for a sample of a radioactive elements mass to be halved due to radioactive decay
What is a chain reaction
Any process in which the material that starts the reaction is also one of the products
The six basic features of a controlled fission nuclear reactor
Fuel system Moderator Heat exchanger Cooling system Containment building Control rods
The importance of critical mass in a fission reaction
It is the smallest mass of fissionable material that will sustain a chain reaction
What is fusion
A nuclear reaction in which two lightweight nuclei combine to form a more massive nucleus with the simultaneous release of energy
A fusion reaction requires
Intense temperature and pressure
A fusion reaction does not require a what does Albert einsteins special theory of relativity conclude?
Energy and mass are interchangeable. Energy and mass are merely different aspects of the same physical phenomenon
What is a mass defect?
Difference between mass of an atoms components and the mass of an atoms nucleus
Why are the nuclei of some atoms more stable than others?
Some have a greater binding energy per nuclear particle
