Physics Exam 3

Front 1

Temperature is generally proportional to a substance's

Back 1

average translational kinetic energy

Front 2

When three-fourths of a container of hot water is poured into a second empty container, the second container then has

Back 2

all of the following
1) 3/4 the thermal energy
2) 3/4 the original volume of water
3) the same temperature

Front 3

Water freezes at a temperature of

Back 3

0 degrees celsius, 273 degrees K

Front 4

Heat is simply another word for

Back 4

thermal energy that flows from hot to cold

Front 5

To say that water has a high specific heat capacity is to say that water

Back 5

absorbs a lot of energy for a small increase in temperature (remember the inverse relationship between heat capacity and temperature change

Front 6

A bimetallic strip used in thermostats relies on the fact that different metals have different

Back 6

rates of thermal expansion

Front 7

The density of water at 4 degrees Celsius will slightly increase when it is
a) cooled
b)warmed
c)both
d)neither

Back 7

d) neither. It decreases if cooled or warmed from 4 degrees Celsius.

Front 8

A firewalker walking barefoot across hot wooden coals depends on wood's

Back 8

poor conduction

Front 9

Thermal convection is linked mostly to

Back 9

fluids

Front 10

A high-temperature source radiates relatively

Back 10

short wavelengths

Front 11

Describe temperature. (how it is measured, what effects it has on matter, what units are used to measure it)

Back 11

temperature is measured using thermometers of various kinds in units of fahrenheit, celsius, and kelvin. Temperature is how hot or cold a substance is. Temperature is proportional to the average translational (to and fro linear) kinetic energy per molecule in a substance.

Front 12

Explain how a thermometer works.

Back 12

A thermometer measures its own temperature. When a thermometer is in contact with a substance, thermal energy flows between the two until equilibrium is established. So when we read a thermometer, we are learning about the temperature of the substance with which it reaches thermal equilibrium.

Front 13

Compare heat and temperature

Back 13

Heat is the total energy of molecular motion in a substance while temperature is a measure of the average energy of molecular motion in a substance. Heat energy depends on the speed of the particles, the number of particles (the size or mass), and the type of particles in an object. Temperature does not depend on the size or type of object. For example, the temperature of a small cup of water might be the same as the temperature of a large tub of water, but the tub of water has more heat because it has more water and thus more total thermal energy.

Front 14

What is absolute zero?

Back 14

the lowest temperature that is theoretically possible, at which the motion of particles that constitutes heat would be minimal. It is zero on the Kelvin scale, equivalent to –273.15°C or –459.67°F.

Front 15

Describe specific heat capacity

Back 15

the heat required to raise the temperature of the unit mass of a given substance by a given amount (usually one degree).

Front 16

Define heat.

Back 16

Heat is thermal energy in transit. After heat has been transferred to an object, it ceases to become heat and is "thermal energy."

Front 17

Discuss thermal expansion

Back 17

thermal expansion, the general increase in the volume of a material as its temperature is increased. It is usually expressed as a fractional change in length or volume per unit temperature change; a linear expansion coefficient is usually employed in describing the expansion of a solid, while a volume expansion coefficient is more useful for a liquid or a gas. If a crystalline solid is isometric (has the same structural configuration throughout), the expansion will be uniform in all dimensions of the crystal. If it is not isometric, there may be different expansion coefficients for different crystallographic directions, and the crystal will change shape as the temperature changes.

Front 18

How do conduction, convection, and radiation differ? Describe each.

Back 18

Conduction is the transfer of heat between substances that are in direct contact with each other. The better the conductor, the more rapidly heat will be transferred.
Thermal energy is transferred from hot places to cold places by convection. Convection occurs when warmer areas of a liquid or gas rise to cooler areas in the liquid or gas. Cooler liquid or gas then takes the place of the warmer areas which have risen higher. This results in a continous circulation pattern. Water boiling in a pan is a good example of these convection currents. Another good example of convection is in the atmosphere.
Radiation is a method of heat transfer that does not rely upon any contact between the heat source and the heated object as is the case with conduction and convection. Heat can be transmitted though empty space by thermal radiation often called infrared radiation. This is a type electromagnetic radiation . No mass is exchanged and no medium is required in the process of radiation. Examples of radiation is the heat from the sun, or heat released from the filament of a light bulb.

Front 19

Define terrestrial radiation

Back 19

Long wave radiation that is emitted by the earth back into the atmosphere. Most of it is absorbed by the water vapor in the atmosphere, while less than ten percent is radiated directly into space.

Front 20

Fahrenheit to Celcius, Celcius to Kelvin

Back 20

Tc = 5/9(Tf-32)

Tk = Tc + 273

(Kelvin does not use the degree symbol)

Front 21

When you brush your hair and scrape electrons from your hair, the charge of your hair becomes

Back 21

positive

Front 22

According to Coulomb's law, a pair of particles that are placed twice as close to each other will experience forces

Back 22

four times as strong (non-inverse square because closer, not farther)

Front 23

When you buy a water pipe in a hardware store, the water isn't included. When you buy copper wire, electrons

Back 23

are already in the wire.

Front 24

To receive an electric shock, there must be

Back 24

a difference in potential across part or all of your body

Front 25

A 10-ohm (Omega) resistor carries 10 amps (A). The voltage across the resistor is

Back 25

More than 10 V.
formula:
current = voltage/resistance
in units:
amps = volts/ohms
for this problem:
10 = x/10
x = 10(10)
x = 100

Front 26

You can touch and discharge a 10,000-V Van de Graaf generator with little harm because, although the voltage is high, there is relatively little

Back 26

energy

Front 27

Compared with the amount of current in the filament of a lamp, the amount of current in the connecting wire is

Back 27

the same

Front 28

As more lamps are connected to a series circuit, the overall current in the power source

Back 28

decreases

Front 29

As more lamps are connected to a parallel circuit, the overall current in the power source

Back 29

increases

Front 30

The difference between dc and ac in electrical circuits is that in dc

Back 30

charges flow in one direction

Front 31

Understand the difference between positive and negative charges, and understand
their interactions based on Coulomb’s Law

Back 31

The force between two charged particles varies directly as the product of their chargges and inversely as the square of the separation distance.
F = k(q1q2/d^2) where k is the proportionality constant 9 x 10^9 N(m^2)/C^2

Front 32

compare electrical forces with gravitational forces

Back 32

Electrical force is both attractive and repulsive because there are both positive and negative charges. Gravitational force is only attractive. Electrical force is much stronger than gravitational. Both have infinite range and the same spatial dependence.

Front 33

Differences between conductors, semiconductors, and insulators.

Back 33

Conductor: Conductors are materials that obey Ohm's law and have very low resistance. They can therefore carry electric currents from place to place without dissipating a lot of power.
In fact, although it sounds odd, modern resistors are also made of conductor materials. However, they use very thin pieces of conductor which don't pass current too easily.

A semiconductor will carry electric current, but not as easily as a normal conductor. Some materials are intrinsic semiconductors. However, most of the semiconducting materials used in electronics are extrinsic. This means that left to themselves they are excellent insulators, turned into semiconductors by doping them with small amounts of foreign atoms.

Insulators like silk, cotton, PVC, and even air refuse to carry current.

Front 34

Understand superconductivity

Back 34

If mercury is cooled below 4.1 K, it loses all electric resistance. This discovery of superconductivity by H. Kammerlingh Onnes in 1911 was followed by the observation of other metals which exhibit zero resistivity below a certain critical temperature. The fact that the resistance is zero has been demonstrated by sustaining currents in superconducting lead rings for many years with no measurable reduction.

Front 35

ampere, volt, ohm, watt, kilowatt-hour.

Back 35

current, voltage (electromotive force, driving one ampere of current against one ohm of resistance), resistance, power (joule per second), thousand watts per hour.

Front 36

ohm's law

Back 36

current = voltage/resistance

Front 37

electric energy vs. electric power

Back 37

Electric power is the rate at which electric energy is transferred by an electric circuit

Front 38

Discuss the difference between direct and alternating currents.

Back 38

AC stands for alternating current, which is an electrical current that frequently reverses direction. AC electricity is measured according to its cycles, with one complete cycle being counted each time a given current travels in one direction and then doubles back on itself.
DC travels in only one direction.

Front 39

Discuss the difference beween a series and a parallel circuit.

Back 39

In a series circuit, the current through each of the components is the same, and the voltage across the circuit is the sum of the voltages across each component.[1] In a parallel circuit, the voltage across each of the components is the same, and the total current is the sum of the currents through each component.[3]
As an example, consider a very simple circuit consisting of four light bulbs and one 6 V battery. If a wire joins the battery to one bulb, to the next bulb, to the next bulb, to the next bulb, then back to the battery, in one continuous loop, the bulbs are said to be in series. If each bulb is wired to the battery in a separate loop, the bulbs are said to be in parallel. If the four light bulbs are connected in series, there is same current through all of them, and the voltage drop is 1.5 V across each bulb, which may not be sufficient to make them glow. If the light bulbs are connected in parallel, the currents through the light bulbs combine to form the current in the battery, while the voltage drop is 6.0 V across each bulb and they all glow.

Front 40

what is overloading a circuit

Back 40

means that more current is flowing through the circuit than the circuit can handle, causing it to break down or malfunction.

Front 41

unit coulomb

Back 41

the charge transported by a constant current of one ampere in one second:

Front 42

Moving electric charged particles can interact with

Back 42

an electric field and/or a magnetic field

Front 43

The magnetic field lines about a current-carrying wire form

Back 43

circles

Front 44

A magnetic force can act on an electron even when it

Back 44

only when it moves and is moving perpendicular to the magnetic field

Front 45

a magnetic force acting on a beam of electrons can change its

Back 45

direction

Front 46

A motor and a generator are

Back 46

similar devices

Front 47

If you change the magnetic field in a closed loop of wire, you induce in the loop

Back 47

current, voltage, and electric field

Front 48

a voltage will be induced in a wire loop when the magnetic field within that loop

Back 48

changes (change is the key word)

Front 49

A galvanometer can be calibrated to read electric

Back 49

current or voltage

Front 50

An electric field is induced in any region of space in which

Back 50

a magnetic field changes with time (again change is the key word)

Front 51

Electricity and magnetism connect to form

Back 51

light

Front 52

What is magnetism?

Back 52

Magnetism is the phenomenon that arises from the force between objects that produce fields that attract or repel other objects.

Front 53

Diagram the way in which magnetic poles interact.

Back 53

two symmetric about the y axis series of nested ellipses, going from long-ways-horizontal to long-ways-vertical.

Front 54

describe the lines of force in a magnetic field

Back 54

Curved lines used to represent a magnetic field, drawn such that the number of lines is related to the strength of the magnetic field at a given point and the tangent of any curve at a particular point is along the direction of magnetic force at that point.

Front 55

What are magnetic domains?

Back 55

A magnetic domain is region in which the magnetic fields of atoms are grouped together and aligned.

Front 56

Describe what condition is caused by moving electrical charges

Back 56

When an electrical charge is moving or an electric current passes through a wire, a circular magnetic field is created.

Front 57

Discuss how an electromagnet works.

Back 57

A coil of wire is wrapped around a core which is then run through with electricity. The coil is set up with a north and south end. The electricity stirs up the electrons, creating a temporarily magnetized effect.

Front 58

What is electromagnetic induction?

Back 58

Electromagnetic induction (or sometimes just induction) is a process where a conductor placed in a changing magnetic field (or a conductor moving through a stationary magnetic field) causes the production of a voltage across the conductor. This process of electromagnetic induction, in turn, causes an electrical current

Front 59

State Faraday’s Law.

Back 59

Electromotive force (or voltage) = change in magnetic flux/ change in time
The induction of voltage when a magnetic field changes with time. If the magnetic field within a closed loop changes in any way, a voltage is induced in the loop.

Front 60

State Maxwell’s counterpart to Faraday’s Law.

Back 60

an electric field is induced in any region of space in which a magnetic field is changing with time. The magnitude of the electrical field is proportional to the rate at which the magnetic field changes.

Front 61

Discuss how a generator works.

Back 61

A generator is simply a device that moves a magnet near a wire to create a steady flow of electrons. The action that forces this movement varies greatly, ranging from hand cranks and steam engines to nuclear fission, but the principle remains the same.

Front 62

Discuss how a motor works.

Back 62

basically makes objects move by using magnet power plus batteries?

Front 63

When we consider the distance a pendulum swings to and fro, we're talking about

Back 63

amplitude

Front 64

If the frequency of a particular wave is 30 Hz, its period is

Back 64

1/30 s

Front 65

In Europe, alternating electric current vibrates to and fro 50 cycles in 1 s. The frequency of these vibrations is

Back 65

50 Hz with a period of 1/50 s

Front 66

If you dip your finger repeatedly onto the surface of still water, you produce waves. The more frequently you dip your finger into the water, the

Back 66

higher the frequency and the shorter the wavelengths

Front 67

The vibrations along a longitudinal wave move in a direction

Back 67

parallel to the wave direction

Front 68

A common example of a transverse wave is
a) sound
b) light
c) both
d) neither

Back 68

b, light

Front 69

when your radio set is tuned to an incoming radio signal, what is occurring?

Back 69

Resonance

Front 70

When sound or light undergoes interference, it can sometimes

Back 70

cancel completely-- and can be equal to, but never greater than, the sum of the amplitudes.

Front 71

What does NOT occur with the doppler effect are changes in

Back 71

speed of sound due to motion

Front 72

a sonic boom is the result of wave

Back 72

superposition

Front 73

Distinguish between waves and particles.

Back 73

waves are movement of particles but the particles are not carried along in the wave. waves can travel through/around obstacles but particles don't.

Front 74

Describe the characteristics of waves: trough, crests, wavelength, period,
frequency, speed, and amplitude.

Back 74

amplitude = height from midpoint to crest
wavelength = distance from one crest to another
frequency = how many to-and-fro vibrations per second
period = time it takes for a complete vibration
trough = bottom crest
speed = frequency x wavelength

Front 75

Discuss the difference in mechanical and electromagnetic waves

Back 75

Electromagnetic waves travel in a vacuum whereas mechanical waves do not. The mechanical waves need a medium like water, air, or anything for it to travel.
Mechanical waves are also called elastic waves as their propagation depends on the elastic properties of the medium through which the waves pass. Electromagnetic waves are caused because of the varying magnetic and electric fields. While mechanical waves are caused by wave amplitude and not by frequency, electromagnetic waves are produced by the vibration of the charged particles. When comparing the speed of mechanical and electromagnetic waves, the former travels at low speed.

Front 76

Describe both transverse and longitudinal wave

Back 76

For transverse waves the displacement of the medium is perpendicular to the direction of propagation of the wave. Ripple.
In longitudinal waves the displacement of the medium is parallel to the propagation of the wave. A wave in a "slinky" is a good visualization. Sound wave.

Front 77

What are sound waves?

Back 77

a wave of compression and rarefaction, by which sound is propagated in an elastic medium such as air.

Front 78

Define and give an example of wave refraction.

Back 78

Refraction is the bending of waves when they enter a medium where their speed is different. Refraction is not so important a phenomenon with sound as it is with light where it is responsible for image formation by lenses, the eye, cameras, etc.

Front 79

Define and give an example of wave reflection.

Back 79

The same behavior is observed with light and other waves, and by the bounce of a billiard ball off the bank of a table. The reflected waves can interfere with incident waves, producing patterns of constructive and destructive interference. This can lead to resonances called standing waves in rooms. It also means that the sound intensity near a hard surface is enhanced because the reflected wave adds to the incident wave, giving a pressure amplitude that is twice as great in a thin "pressure zone" near the surface

Front 80

What is the difference in a forced vibration and the natural frequency?

Back 80

The tendency of one object to force another adjoining or interconnected object into vibrational motion is referred to as a forced vibration. In the case of the guitar string mounted to the sound box, the fact that the surface area of the sound box is greater than the surface area of the string means that more surrounding air particles will be forced into vibration. This causes an increase in the amplitude and thus loudness of the sound.

Front 81

Discuss wave interference, and describe the difference between constructive and
destructive interference.

Back 81

waves can move through each other, which means that they can be in the same place at the same time. This is very different from solid objects.
When the peaks of the waves line up, there is constructive interference. Often, this is describe by saying the waves are "in-phase".
When the first wave is up, the second wave is down and the two add to zero. When the first wave is down and the second is up, they again add to zero. In fact, at all points the two waves exactly cancel each other out and there is no wave left! This is the single most amazing aspect of waves. The sum of two waves can be less than either wave, alone, and can even be zero. This is called destructive interference.

Front 82

Explain resonance.

Back 82

the reinforcement or prolongation of sound by reflection from a surface or by the synchronous vibration of a neighboring object.

Front 83

Describe the Doppler effect.

Back 83

the change in frequency of wave motion resulting from the motion of the wave source or receiver (change in pitch of a siren as it goes from far to near to far)

Front 84

Explain waves, shock waves, and sonic booms

Back 84

a bow wave is produced by overlapping circles that form a V. Shock waves are produced by overlapping spheres that form a cone. Sonic booms are produced by the incidence of a shock wave.

Front 85

Beats

Back 85

a series of alternate reinforcements and cancellations produced by the interference of two waves of slightly different frequency, heard as a throbbing effect in sound waves.

Front 86

what is a standing wave?

Back 86

a stationary wave pattern formed in a medium when two sets of identical waves pass through the medium in opposite directions.