Physics 1140 Self Test
List three ways an object can acquire a static electrical charge
friction direct contact induction
insulators
nonmetal poor conductors
neither a good conductor nor a good insulator
semiconductor
good conductors
silver, gold, and copper
Of the four known forces that occur naturally, which is the strongest and which is the weakest?
strongest; nuclear forces weakest; gravitational forces
Explain how the Dewar flask reduces each type of heat loss to a minimum
A partial vacuum reduces heat transfer by conduction and convection, and the reflective silvered surface of the walls reduces heat transfer by radiation
received a Nobel price is 1907 for studies of light
Albert Michelson
What is an electric field?
An electric field is the region of force that surrounds a charged object
used a rotating toothed wheel to measure the speed of light
Armand Fizeau
formulated three laws of static electricity
Benjamin Franklin
State the three laws of static electricity developed by Benjamin Franklin
Bodies charged with static electricity attract uncharged bodies Like electric charges repel one another Unlike electric charges attract one another
What is capacitance?
Capacitance is the ability of a device to hold a charge
measured forces between charged bodies
Charles de Doulomb
Contrast constructive and destructive interference
Constructive interference occurs when waves arrive in phase and strengthen one another. Destructive interference occurs when waves arrive out of phase and cancel one another
What is diffraction?
Diffraction is a phenomenon in which waves spread out after they pass through a small opening and bend as they pass along the edge of an obstruction
Which statement is most consistent with Lord Rayeigh's beliefs?
Earth was created by God, and its wonders are revealed to man's mind by God
If a charged rod is brought near an electroscope and leaves diverge farther, which of the following is true?
Either both are positive or both are negative
State the law of conservation of charge
Electric charge can neither be created nor destroyed
State Huygens' principle of wave motion
Every point on a wave is itself a source of a new wave motion of the same frequency
What is the potential difference between two points of an electric field?
It is the work-per-unit charge needed to move the charge from one point to the other
showed that light travels 10,000 times faster than Earth in its orbit
James Bradley
used a rotating plane mirror to measure the speed of light
Jean Foucault
observed the eclipse of Jupiter's moon to determine the speed of light
Olaus Roemer
Who found the first useful purpose for electricity, and what did he invent?
Samuel F. B. Morse found the first useful purpose for electricity by inventing the telegraph
Why do scientists have difficulty discovering truth?
Scientists have difficulty discovering truth because they have limited means of observing reality
was the first to investigate static electricity
Thales of Miletus
State Coulomb's law
The force acting between two charges is inversely proportional to the square of the distance between them
Explain the importance of the inverse square law
The inverse square law is important because gravity, sound intensity, magnetic and electric field strength, and light intensity all obey it
What are two ways to increase capacitance?
Two ways to increase capacitance are to increase the charge or to lower the voltage
A body that is charged with static electricity always has ...
an unequal number of protons and electrons
