SCMH 1010 Exam #2

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Which has a greater amount of entropy? Air at 0 C Air at 20 C Air at -20 C Air at 40 C

Air at 40 C

A calories is the amount of heat energy necessary to raise the temperature of one gram of water by one degree

Celsius

Water freezes at 0 in the --- temperature scale

Celsius

The person who defined the nature of the electrical force between two charged bodies was

Charles Coulomb

Who showed that electrical forces could be used to do work, i.e., demonstrated the first electrical generator?

Michael Faraday

electromagnet

a device composed of a coil of wire that produces a magnetic field whenever an electrical charge runs through the wire

wave

a traveling disturbance that carries energy from one place to another

Bats use high-pitched sound waves undetectable to human hearing to detect objects in their environment. This means the wavelength of sounds they use is

above 20,000 Hz

Gamma radiation is a shorter wavelength than: visible light microwaves x-rays radio waves all of the above

all of the above

AC

alternating current; favored by Nikola Tesla

ampere

amount of current that flows in a wire

Turning up the volume of music or speaking louder means that the sound wave has changed

amplitude

What aspect of a sound wave makes it seem loud to people hearing the sound?

amplitude

the height of a wave crest above the undisturbed portion is its

amplitude

a circuit consists of

an energy source, a closed path, and a device that uses electrical energy

temperature is

atomic movement (speed of molecules)

The dipole field is found in

bar magnets

A device that converts stored energy into the kinetic energy of electrons passing through an outside wire is called a(n)

battery

refraction

bent light

visible light of a high frequency is

blue

If you are standing in the path of a source of light that is moving toward you, the light you see will look -- than it would ordinarily

bluer

convection

bulk transfer of molecules

electromagnets are used in

buzzers, switches, and electric motors

The heat island effect in cities creates convection cells

by drawing in cool moist air from the suburbs

The amount of energy required to raise the temperature of one gram of water by 1 degree Celsius is a

calorie

In science, heat is commonly measured in what unit?

calories

heat is measured in

calories

The transfer of heat by direct atomic collisions is referred to as

conduction

What is the only way heat can be transferred within a solid piece of metal

conduction

a spoon in hot water is an example of

conduction

The transfer of heat by density - driven motion of gases or fluids is referred to as

convection

The transfer of heat by the bulk motion of gases or fluids is referred to as

convection

boiling a pot of water is an example of

convection

infrared radiation

converted to thermal energy at its destination

Which substance has the lowest specific heat capacity?

copper

The amount of electrons flowing in a specific direction is termed the

current

When electric charges are in motion we have

current

Voltage is calculated with the following formula

current x resistance

Albert A. Michaelson

demonstrated that light travels without a medium

parallel circuit

different loads are situated on different wire loops

an electric current flowing from a storage battery is

direct current

DC

direct current; favored by Thomas Edison

Ben Franklin

discovered electricity and invented the lightning rod

Hans Christian Oersted

discovered that magnetism and electricity are intimately related when he ran current through a circuit and a nearby compass moved

William Gilbert

discovered the poles in a dipole magnet

Entropy is the measure of a system's

disorder

wavelength

distance between crests (highest points of adjacent waves)

Radiation is heat transfer by

electromagnetic waves of radiation

Static electricity exists when there is an unbalance among the number of

electrons

the force that moves electrically charged objects toward and away from each other is

electrostatic force

entropy can go backward only if

extra energy is introduced

Of the types of radiation listed below, the only one that humans can detect is gamma rays infrared waves visible light x-rays none of the above

none of the above

frequency

number of wave crests that go by a given point every second

In the equation of Ohm's law, resistance is in the unit

ohms

One amp of electrical current is equal to

one coulomb of charge per second

A term that compares how vigorous atoms are moving in a substance is

temperature

Temperature is a measure of

the average kinetic energy of the atoms within a substance

Daniel Fahrenheit invented temperature scale for which 0 represented

the coldest temperature he could obtain for salt water

What direction does energy move in?

the direction of the wave

electric field

the force exerted on its surroundings by a charged object

electricity

the force that moves objects toward and away from eachother

when we hear a sound change from a higher to a lower pitch, this means

the frequency has changed

an efficient engine has

the least amount of disorder possible (the most work that the engine allows from the energy put in)

In a transverse wave

the motion of the medium is perpendicular to the motion of the wave

Why does lightning occur?

the negative charges in the cloud are attracted to the positive charges on the ground

The higher the frequency of a sound wave

the shorter the wavelength

The velocity of all electromagnetic radiation is

the speed of light

Coulomb's law states that the force of static electricity between two objects is inversely proportional to

the square of the distance between the objects

Fahrenheit =

(1.8 x C) + 32

Celcius =

(F - 32) / 1.8

Which of these represents the coldest temperature? 0 degree Celsius Freezing point of CO2 (dry ice) 0 degrees Kelvin -100 degrees Celsius 0 degrees Fahrenheit

0 degrees Kelvin

gamma rays

0.1 nm - 1 x 10^-12 m

A particular electrical appliance requires 30 W. When it is connected to a power source that provides 120 V, the current in the circuit is

0.25 A

radiowaves

1 KHz - 1 MHz

herts (HZ) =

1 cycle / 1 second

microwaves

1 m - 1 mm

infrared radiation

1 mm - 1 micron

2nd law of thermodynamics

1. heat does not flow spontaneously from hot to cold. 2. no engine can exclusively convert heat to work 3. every isolated system tends toward disorder

How much amperage will be moving through a wire if it has a resistance of 12 ohms and is carrying 120 V?

10 Amps

x-rays

100 nm - 0.1 nm (smaller than an atom)

The voltage across a resistor is 20 and the current through it is 10 A. What is the resistance o the resistor?

2 ohms

The current through a 5 ohm resistor is 0.40 A. What is the voltage across the resistor?

2.0 V

How fast can light travel in one second, if it is moving through a vacuum?

300,000 km

all electromagnetic waves travel at

300,000 km/sec

In the Kelvin scale, water boils at

373 K

twenty calories of heat energy will raise the temperature of five grams of water

4 C

ultraviolet radiation

400 nm - 100 nm

Which sound wave frequency is outside the range of a human's ability to detect? 200 Hz 5 Hz 2000 Hz 10000 Hz 20 Hz

5 Hz

If the temperature of an object changes by 5 C then it also changes by

5 K (kelvin)

The current in a circuit is 0.5 A and the voltage across it is 12 V. The power being supplied by the source is

6 W

1 coulomb =

6.3 x 10^18 electrons

visible light

700 nm - 400 nm

k =

8.99 x 10^9

Approximately how much power is consumed per hour by an electric stove drawing 40 amps? (The stove is plugged into a 240 volt wall socket).

9.6 kW/hr

which of the following statements is not consistent with the second law of thermodynamics? all isolated systems will tend to remained ordered indefinitely heat will not flow spontaneously from a cold body to a hot body no engine is 100% efficient in converting energy to work the evolution of more complicated forms of life on earth does not annul the second law

All isolated systems will tend to remain ordered indefinitely

The unit for electric current is what?

Amps

electrical current is measured in

Amps

A bar magnet is magnetic even when no electric current is passing through it. Why?

Bar magnets take advantage of the electrons moving around in atoms to create a magnetic field.

the historical figure who demonstrated that lightning was electrical in nature was

Benjamin Franklin

A car converts energy and therefore represents a system. If gasoline is the material input, what is the material output?

CO2 emissions to the atmosphere

DC refers to

Direct current

the increase in frequency of an approaching source of electromagnetic radiation is termed to

Doppler effect

Some migratory birds use the following to guide them on long flights lightning static electricity earth's magnetic field electrical signals from the Earth

Earth's magnetic field

Which is more powerful? The force of gravity or electrical force?

Electrical force

In what way does Newton's law of universal gravitation differ from Coulomb's law?

Electrical forces can be either attractive or repulsive, while gravity is only attractive

Luigi Galvani

Electrical stimulation of the nerve in a frog's leg produced contraction of the leg muscle

electric motors

Employ a pair of permanent magnets and a rotating loop of wire inside the poles of the magnets

Michael Faraday

English chemist who created the first simple electric motor and the first dynamo

Which statement best represents the second law of thermodynamics? Heat will not flow spontaneously from a hot to a cold body. Scientists have constructed an engine that does nothing but convert heat to useful work. The total amount of energy in the universe is constant Every isolated system becomes more disordered with time. Energy may change from one form to another over and over again.

Every isolated system becomes more disordered with time.

Coulomb's law

F = K x (q1q2/d^2)

Another way of stating the Second Law of Thermodynamics is which of the following? In order to decrease the entropy of a system, work must be done on it by an external agent. It is impossible to decrease the entropy of a system In order to increase the entropy of a system, work must be done on it by an external agent. The entropy of any system remains constant or increases.

In order to decrease the entropy of a system, work must be done on it by an external agent.

Who authoritated entropy?

Ludwig Boltzmann

Name Electromagnetic Waves long to short

Radiowaves, microwaves, infrared, visible light, ultraviolet, x-rays, gamma rays

Conductors are materials with relatively low

Resistance

Which of the following is totally a longitudinal wave?

Sound

Which of the following is the definition of a calorie?

The amount of heat required to raise the temperature of 1 g of water initially at room temperature by 1 C

What is "heat death"?

The notion that the earth will ultimately be destroyed when all heat becomes heat waste

efficiency =

[(T hot - T cold) / T hot ] x 100

The Doppler effect decribes

change in a wave frequency when source or receiver is moving

Electric fields and electric currents can be produced by

changing magnetic fields

what causes the northern lights?

charged particles streaming from the sun can emit light when they interact with a magnetic field

heat is

energy in motion (amount of energy capable to do work)

radiation

energy that doesn't need a travel medium

A system that moves toward a higher state of order also moves toward a lower state of

entropy

All isolated systems will spontaneously tend toward disorder. This phenomenon is referred to as

entropy

Freezing ice from liquid water is an example of going to a lower state of

entropy

What are some things used to insulate homes today?

fiberglass, double paned windows, sheets of styrofoam

static electricity

force/energy resting on an object

Which property of electromagnetic waves is measured in Hertz?

frequency

objects from which electrons are removed

gain a positive charge

Which of the following has the shortest wavelength? fm radio waves am radio waves microwaves gamma rays

gamma rays

Sound waves with low frequencies:

have low pitches

amplitude

height of the wave crest above the undisturbed portion

heat will only flow spontaneously from

hot to cold

electrical resistance

how hard it is to push electrons through wires

cats' eyes are more sensitive to --- than humans'

infrared waves

Alessandro Volta

invented the battery

In a longitudinal wave, the motion of the medium

is parallel to the direction of the wave

The collection of lines that map out the directions in which compass needles would point is called a(n)

magnetic field

entropy is

measure of disorder

In his famous experiment of the late 1700s, Charles Coulomb

measured the force of the electric charge in objects

which of the following materials has the highest thermal conductivity? wood metal air fur

metal

Line of sight communications and radar rely heavily on what type of electromagnetic wave?

microwaves

Absolute zero is defined as the temperature a which

molecular and atomic vibration is zero; all heat extracted

You add heat to a solid and cause it to melt. The resulting configuration is

more disordered and at higher entropy

longitudinal wave

motion is in the same direction as the wave

transverse waves

motion is perpendicular to wave direction

conduction

movement of heat by atomic scale collision

Which of the following can produce magnetic fields?

moving electrical charges

Lazzaro Spallanzani

mutilated bats to find out that they locate food through hearing

load

power = v x c

voltage

pressure produced by the energy source

The standard use to calibrate Celsius thermometers is

pure water

Sunlight hitting dark roof tiles would and heating up a house would be an example of

radiation

The transfer of heat in the form of electromagnetic waves is called

radiation

a fire transfers most of its heat by

radiation

a fireplace or space heater is an example of

radiation

Energy can be transferred through a vacuum by

radiation only

visible light of a low frequency is

red

When light passes through a transparent material, its direction is usually changed slightly. This is called

refraction

Another word for constructive interference is

reinforcement

As energy is transferred from one trophic level to the next

some energy is always lost in the form of heat

The measure of the ability of a material to absorb heat is referred to as its

specific heat capacity

Which of the following is the same for all kinds of electromagnetic waves?

speed

velocity

speed and direction of wave crest

Through which material will heat be conducted the best?

steel

Maxwell's Equations

there are no magnetic monopoles in nature Coulomb's law: like charges repel, unlike attract magnetic phenomena can be produced by electrical effects electrical phenomena can be produced by magnetic effects

The measure of the quantity of heat contained in an object is referred to as its

thermal energy

period

time between adjacent waves, inverse of frequency (1 second / 1 wave)

The fundamental difference between electromagnetic waves and other types of waves is that electromagnetic waves:

transfer energy without transferring mass

electricity and magnetism are

two aspects of one force

series circuit

two or more loads are linked along a single loop of wire

Which type of radiation can be used to sterilize medical equipment?

ultraviolet radiation

Ohm's Law

v = c x r

wavelength formula

v = lamba x f

Ohm's Law states

voltage = current x resistance

what substance has the highest specific heat capacity?

water

absorption

wave and energy are absorbed

transmission

wave passes through matter

The distance between crests in a wave is its

wavelength

What are the properties of a wave

wavelength, frequency, amplitude, period, and velocity

constructive interference

waves act together (amplitude is increased)

scattering

waves are absorbed and reemitted (disuse scattering and reflection)

destructive interference

waves cancel each other out

human eyes are most sensitive to this color

yellow

Which device would most likely be running on DC electricity?

your cell phone


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