Chapter 16: Heat Transfer

Question 1

Object in thermal contact at different temperature tend to reach a common temperature in three ways

Answer 1

1) Convection
2) Conduction
3) Radiation

Question 2

1) Convection

Answer 2

The transfer of heat through a fluid (liquid or gas) caused by molecular motion

Question 3

2) Conduction

Answer 3

The transfer of heat or electric current from one substance to another by direct contact

Question 4

3) Radiation

Answer 4

Energy that is radiated or transmitted in the form of rays or waves or particles

Question 5

Conduction (2nd)

Answer 5

Transfer of internal energy by electron and molecular collisions within a substance, especially a solids

Question 6

Conduction occurs when two objects of different temperatures come in

Answer 6

Direct contact with each other

Question 7

Heat is transferred from the high temperature object toward the low temperature object from

Answer 7

The collisions between the particles at the contact area of the objects

Question 8

Collisions continues to transfer energy until the temperature of the two objects are

Answer 8

Identical

Question 9

A blacksmith heating up a sword in hot coals, and the heat

Answer 9

Transferring up through the metal

Question 10

A lizard sunbathing on a warm rock to

Answer 10

Raise their body temperature

Question 11

Swiftly are transfer

Answer 11

Heat

Question 12

Metals are excellent conductors tend to

Answer 12

Have more free electrons ready to transfer energy via collisions

Question 13

Fluids tend to be

Answer 13

Poor conductors

Question 14

Poor conductors are

Answer 14

Great insulators

Question 15

Insulators tightly held electrons

Answer 15

Vibrate in place and transfer energy slowly

Question 16

Insulators impede the transfer of

Answer 16

Heat

Question 17

Insulators wool, paper, feathers, and snow are

Answer 17

Great insulators they trap air

Question 18

Air are both

Answer 18

1) Poor Conductor
2) Good Insulator

Question 19

The rate of heat flow from the hot air to your relatively cool hand is

Answer 19

Low

Question 20

Insulation does not prevent the flow of

Answer 20

Internal energy

Question 21

Insulation slow the rate at which

Answer 21

Internal energy flows

Question 22

Rock wool or fiberglass between walls slows the transfer of internal energy from a warm house to

Answer 22

A cool exterior in winter, and the reverse in summer

Question 23

Snow patterns on the roof of a house shows areas of

Answer 23

Conduction and insulation

Question 24

Bare patches show where heat from inside has leaked through the

Answer 24

Roof and melted the snow

Question 25

Convection

Answer 25

Transfer of heat involving only bulk motion of fluids

Question 26

Convection occurs when heat is transferred from

Answer 26

The movement of heated fluids (liquids and gases)

Question 27

Convection heated fluids expand and become

Answer 27

Less dense

Question 28

Lower density fluid rises while the higher density fluid sinks resulting in the formation of

Answer 28

Convection currents

Question 29

Convection currents allow the heat to be

Answer 29

Spread throughout the fluid

Question 30

Warm air rises expands, becomes less dense, and is

Answer 30

Buoyed upward (Archimedes)

Question 31

It rises and cools until its density

Answer 31

Equals that of the surrounding air

Question 32

Convection cooling by

Answer 32

Expansion that opposite to the warming that occurs when air is compressed

Question 33

A combination of air expansion and mixing with

Answer 33

Cooler surrounding air

Question 34

Although warm air rises, why are mountaintops colder and snow covered, while the valleys below are relatively warm and green?

Answer 34

1) Warm air cools when rising 2) There is a thick insulating blanket of air above the valley Both of the answers

Question 35

Winds result of

Answer 35

Unevent heating of the air near the ground

Question 36

Wind's absorption of Sun energy occurs more readily on

Answer 36

Different parts of Earth's surface

Question 37

Sea breeze

Answer 37

The ground warms more than water in the daytime

Question 38

Warm air close to the ground rises and is replaced by

Answer 38

Cooler air from above the water

Question 39

Radiation

Answer 39

Transfer of energy from the Sun through empty space

Question 40

Radiation occurs when electromagnetic waves are

Answer 40

Transmitted from an origin to the space surrounding it

Question 41

Unlike with conduction and convection and it does not rely upon any contact between

Answer 41

The heat source and the heated object

Question 42

All objects carry energy in the form of

Answer 42

Electromagnetic waves and the hotter the object, the more it radiates

Question 43

Radiant energy emitted by

Answer 43

All bodies, transferred through space

Question 44

Radiant energy exists as

Answer 44

Electromagnetic waves ranging from long (radio waves) to short wavelengths (X-ray/Gamma)

Question 45

Radiant energy includes visible light, ranging from

Answer 45

Longer waves (red) to shorter waves (violet)

Question 46

Wavelength of radiation related to frequency of

Answer 46

Vibration of an electromagnetic wave

Question 47

Wavelength of radiation are

Answer 47

Inversely proportional

Question 48

Low frequency vibration implies

Answer 48

Long wavelength waves

Question 49

High frequency vibration implies

Answer 49

Short wavelength waves

Question 50

Frequency of radiation is

Answer 50

Proportional to the absolute temperature of the source

Question 51

If an object is hot enough, some of the radiant energy it emits is

Answer 51

In the range of visible light

Question 52

Every object above absolute zero radiates: Sun produces solar radiation including

Answer 52

Visible light

Question 53

Earth produces terrestrial radiation in the form of

Answer 53

Infrared waves

Question 54

Frequencies beneath the threshold for our eyes to

Answer 54

Detect as visible light

Question 55

The surface of Earth loses energy to outer space due mostly to

Answer 55

Radiation

Question 56

Range of temperature of radiating objects

Answer 56

1) Room temperature emission is in the infrared (20 to 22 degrees Celcius) 2) Temperature above (500 degrees Celcius), red light emitted, longest waves visible 3) About (600 degrees Celcius), yellow light emitted 4) At (1500 degrees Celcius), object emits white light whole range of visible light

Question 57

The colors of stars

Answer 57

Hottest (Blue, blue white), and Mid (Yellow), and (Orange, Red) for Coldest

Question 58

Why body glows with electromagnetic waves?

Answer 58

Sun and the Earth

Question 59

The absorption of radiant energy occurs along with

Answer 59

Emission of radiant energy

Question 60

Any material that absorbs more than it emits is

Answer 60

A net absorber

Question 61

Any material that emits more than it absorb is

Answer 61

A net emitter

Question 62

Net absorption or emission is

Answer 62

Relative to temperature of surroundings

Question 63

Good absorbers are

Answer 63

Good emitters

Question 64

Poor absorbers are

Answer 64

Poor emitters

Question 65

If a good absorber of radiant energy were a poor emitter, its temperature compared with

Answer 65

Its surroundings would be higher

Question 66

A hot pizza placed in a snow is

Answer 66

A net emitters

Question 67

Reflection of radiant energy this is a opposite to

Answer 67

Absorption of radiant energy

Question 68

Any surface that reflects very little or no radiant energy

Answer 68

"Looks" dark

Question 69

Radiation openings appear black because

Answer 69

1) Light that enters them is reflected on the inside walls many times 2) Partly absorbed at each reflection are good absorbers

Question 70

Good reflectors are

Answer 70

Poor absorbers

Question 71

A black object readily

Answer 71

Absorbs visible light

Question 72

Newton's Law of Cooling were the rate of cooling is

Answer 72

Approximately proportional to the temperature difference and heat between the object and its surrounding

Question 73

Newton's Law of Cooling also applies to

Answer 73

Rate of warming

Question 74

An object cooler than its surroundings warm up at

Answer 74

A rate proportional to heat proportional

Question 75

Frozen food will warm faster in

Answer 75

A warm room than in a cold room (defrosting)

Question 76

The Greenhouse effect named after a similar temperature raising effect in

Answer 76

Florists greenhouse

Question 77

Short wavelength radiation from the Sun is

Answer 77

Transmitted through the glass

Question 78

Long wavelength reradiated energy is

Answer 78

Not transmitted out through the glass and is trapped inside

Question 79

All things radiate at frequencies (and therefore wavelengths) determined by

Answer 79

The temperature of the emitting object

Question 80

Things (such as glass) can be transparent to some wavelengths but

Answer 80

Opaque or reflective to others

Question 81

Sun's rays are very short and pass through

Answer 81

The car's windows

Question 82

Absorption of Sun's energy

Answer 82

Warms the car interior

Question 83

Car interior radiates its own waves, which are longer and do not transmit through

Answer 83

The window

Question 84

Car's radiated energy remains inside, making the car's interior

Answer 84

Very warm

Question 85

Global warming: Energy is absorbed from

Answer 85

The sun and partly reradiated by Earth as longer wavelength terrestrial radiation

Question 86

Global warming: Terrestrial radiation is absorbed by

Answer 86

Atmospheric gases and re-emitted as long wavelength terrestrial radiation back to Earth

Question 87

Global warming: Reradiated energy unable to

Answer 87

Escape, so warming of Earth occurs

Question 88

The greenhouse gases that contribute to

Answer 88

Global warmings absorb more infrared radiation than visible