Physics 1140 Self Test

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

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

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

A body that is charged with static electricity always has ...

an unequal number of protons and electrons

Of the four known forces that occur naturally, which is the strongest and which is the weakest?

strongest; nuclear forces weakest; gravitational forces

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

What are two ways to increase capacitance?

Two ways to increase capacitance are to increase the charge or to lower the voltage

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

received a Nobel price is 1907 for studies of light

Albert Michelson