Heat, Sound and Light Flashcards

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1
Q

What’s heat?

A

Heat is the energy that flows between two substances of different temperature

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2
Q

what direction does heat flow?

A

From a warm substance to a cold substance

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3
Q

Which defines the average kinetic energy of a system’s particles?

A

temperature

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4
Q

A hot metal plate at 150°C has been placed in air at room temperature. Which event would most likely take place over the next few minutes?

A

The air molecules that are surrounding the metal will speed up, and the molecules in the metal will slow down.

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5
Q

What is a exothermic reaction?

A

A reaction that releases heat

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6
Q

What is a endothermic reaction?

A

A reaction that absorbs energy

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7
Q

In an exothermic reaction, the environment gets?

A

hotter

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8
Q

In an endothermic reaction, the environment gets?

A

colder

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9
Q

Uses of endothermic reactions?

A

ice packs

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10
Q

Uses of exothermic reactions

A

hand warmers

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11
Q

Examples of exothermic reactions

A

combustion, oxidation, neutralization

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12
Q

The process of a solid to a gas is called..

A

sublimation

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13
Q

Example of sublimation

A

dry ice

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14
Q

The process of gas to a solid is called..

A

deposition

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15
Q

What is heat/thermal energy?

A

Kinetic energy of the particles inside matter.

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16
Q

Unit of thermal energy

A

Joules (J)

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17
Q

Difference between temperature and heat

A

Temperature: measure of
how hot the object is
measured in C*

Heat: The total kinetic energy of the particles in a matter

Measure in Joules (J)

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18
Q

What thermal equilibrium

A

when the heat transfers from a hot object to a cool object until both the objects have the same temperature

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19
Q

Which one has more heat:

A bowl of soup having a temperature of 75°C or the sea at Portrush has a summer temperature of 17°C.

A

The sea because it has more particles than the soup therefore more thermal energy

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20
Q

What’s heat transfer?

A

The transfer of heat from a higher temperature to a lower temperature

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21
Q

Define Conduction

A

flow of heat energy from high temperature to low temperature without overall movement of the material

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22
Q

Which particle model does conduction mainly occur

A

Solid

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23
Q

What two particle models are really bad conductors (Insulators)

A

Liquid and gas

24
Q

Why are metals good conductors?

A

They have free electrons

25
Q

why are hair, fur, feathers and wool are good insulators

A

because they trap heat

26
Q

What’s convection?

A

flow of heat energy from high temperature to low temperature by movement of a fluid.(liquid and gases)

27
Q

Describe convection

A

When part of a liquid or gas is heated it expands, becomes less dense and rises. It is replaced by the cooler, denser fluid.

This liquid or gas is in turn heated, expands becomes less dense and rises. Therefore creating convection currents

28
Q

What is radiation?

A

transfer of heat from high to low temperature through INFARED radiation

29
Q

how does radiation travel

A

it travel through vacuum with no medium (Sun radiates heat to earth through vacuum)

30
Q

What are the best absorbers and emitters of heat

A

Dull Black Surfaces

31
Q

What are poor absorbers and emitters of heat but GOOD REFLECTORS

A

Shiny Surfaces

32
Q

how does radiation relate to greenhouse

A

when the suns radiation warms up the earth it gets reflected to the atmosphere which in turn reflects to space or CO2 present in the atmosphere absorbs it cause the earth to warm up

33
Q

how does vacuum flask

A

A vacuum flask uses a vacuum and reflective coating to minimize heat transfer by conduction, convection, and radiation, keeping liquids hot or cold for extended periods.

34
Q

How does sound travel?

A

Sound travels in waves(it needs a medium-air)

35
Q

How is sound created?

A

Sound is created by vibrations

36
Q

what are the different types of sound waves and explain each

A

Longitudinal wave-parallel to the direction in which the waves travel

Transverse wave-perpendicular to the direction in which the waves travel

37
Q

sound travels by several compressions and rarefactions

T/F

A

TRUE

38
Q

How do you know that the sound has high amplitude by looking at its compressions and rarefactions

A

The more compressed the air molecule, the higher the pressure which means the higher the volume

39
Q

How is sound measured?

A

decibels (dB)

40
Q

how to identify its high pitch by looking at the waves

A

it would have more frequency

41
Q

why in space no one can hear you scream

A

sound travels through a medium such as air but there’s no medium on space that’s why no one can hear u scream on space

42
Q

which colour has the longst wavelenght

A

RED

43
Q

Whta colour has the shortest wavelength

A

Violet

44
Q

what color refracts the least

A

RED

45
Q

How does light travel?

A

Light travels in straight lines

46
Q

how does light change direction

A

Using reflections and refractions

47
Q

what is the law of incidence

A

angle of incidence = angle of reflection

48
Q

What type of waves are light?

A

Transverse

49
Q

Light waves change ______ when they pass across the boundary between two substances with a different density, such as air and glass. This causes them to change direction, an effect called refraction.

A

Speed

50
Q

what happens to the Light passing from a less dense to a more dense medium?

A

the ray bends toward the normal.

51
Q

what happens to the light passing from a more dense to a less dense medium

A

the ray bends away from the normal.

52
Q

What is dispersion?

A

The splitting of white light into its colours

53
Q

Objects appear black in white light because…

A

they absorb all colors and reflect none.

54
Q

concave lens?

A

spreads light out

55
Q

Convex lens?

A

bends light inwards

56
Q

what are convex lens used for?

A

To magnify small objects

57
Q

what are concave lens used for?

A

used in glasses for short sightedness