# مراجعة هيكل امتحان العلوم انسباير الصف الثامن الفصل الثاني

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مراجعة هيكل امتحان العلوم انسباير الصف الثامن الفصل الثاني

#### Transferring charge

Charged particles transfer between two conductors is called transferring charge by conduction

As shown in the figure above Charged particles flow from the object with a greater concentration of negative charge to the object with a lower concentration. Similar to water flowing from a container with higher water level to a container with a lower level

The flow Of charged particles continues until the concentration Of charge on both objects is equal

Conservation Of charge

Notice that the amount of water didn't change. The amount of water that started in the full container is the same as the amount of water after the two containers become equal, This is similar to the charged particles flowing between the two conductive objects

Which statement explains why the socks cling to the blanket

A) The socks and blanket dried together which caused them to cling to each other

B) The socks and blanket are conductors that picked up some positive charges that keep the clothes together

C) The socks and blanket are insulators that picked up some negative charges that keep the clothes together,

D) The clothes picked up opposite charges. The opposite charges are attracted to each other

Which solution would reduce this problem in a dryer

A) crinkled- up ball of aluminum foil will conduct the charges and remove the charges from the clothes

B) Place less clothes in the dryer to prevent rubbing

C) Lower the electricity the dryer uses to lower the number of charges in the dryer

D) Dry clothes without them touching so that the clothes do not dry together

Lesson 3: Simple Circuit

1. A source Of electric energy "battery"

2. An electric device "light bulb"

3. An electric conductor "wire"

4. A switch "on, Off"

2) Absorption

Is the transfer Of energy by a wave to the medium through which it travels

The amount of energy absorbed depends on

• The type Of wave

• The material in which it moves

In the figure on the right the sound from the cell phone is absorbed by the insulation in the wall

3) Transmission

Is the passage Of a wave through a medium. The sound from a cell phone in the figure on the right transmits easily through an uninsulated wall

Without transmission we would not hear sound waves on the Other side of doors

Speed of Sound

Two factors that influence the speed of sound waves are

1. The density

2. The temperature of the medium

Gas particles are far apart and collide less Often than particles in a liquid or a solid. As shown in the table on the right, a gas takes longer to transfer sound energy between particles. In a solid where the particles are packed very close together, the particles collide and transfer energy very quickly. The more dense medium, the faster sound will travel through it

Temperature

Particles move faster and collide more Often as the temperature Of a gas increases. This increase in the number Of collisions transfers more energy in less time. Temperature has the opposite effect on liquids and solids. As liquids and solids cool, the molecules move closer together. They collide more often and transfer energy faster

In liquids and solids, increasing temperature

decreasing the speed of Sound

You are in a sound -proofed hallway. Someone standing around the corner from you speaks and you hear them. Which claim offers the best evidence and reasoning for this phenomenon

A) Sound is not affected by types of materials, because sound can travel though solids, liquids, and gases

B) Sound waves are absorbed by the sound- proofed walls and then transmitted through the wall to your ear

C) Sound waves diffract so even though the walls do not reflect the sound wave, the sound wave can still travel to your ear

D) Sound -proof walls allow sound waves to reflect all of the sound that is directed toward them. So, the sound must bounce off them and go to your ear

Questions

This is the term that describes when light passes through matter

A) Transmission

B) Transparent

C) Translucent

D) Opaque

Which Of the following is NOT a cause Of a wave changing direction

A) Reflection

B) Transmission

C) Radiation

D) Absorption

When a wave bends or spreads past a medium, this is referred to as

A) Reflection

B) Refraction

C) Radiation

D) Diffraction

4) Sound travels faster in

A) solids

B) gas

C) water

D) air

Movie theaters use sound proofing to reduce echoes, Soundproofing materials are designed to the sound

A) Absorption

B) Transmission

C) Diffraction

D) Reflection

Which Of the following is NOT a way that waves interact with matter

A) Waves can be reflected by matter

D) As waves pass through matter, some Of the energy they carry can be transferred to matter

7) Which type Of interaction is this

A) reflection

B) refraction

C) diffraction

8) Which type Of interaction is this

A) reflection

B) refraction

C) diffraction

A) Waves can be reflected by matter

B) Waves are affected by gravity

C) Waves can transfer energy to the medium through which it travels

B) refraction

Which type Of interaction is this

reflection

diffraction

Which type Of interaction is this

reflection

refraction

diffraction

Sound travels FASTEST through which of these materials

A) Air

B) Empty space

C) solid

D) Water

Sound does not travel in space because

A) Space is too far away

B) There is no matter in space

C) The energy is too weak

D) The sound from our surrounding id too

Why is the school library covered with carpet

So, everyone can make a lot of noise to help absorb sounds to keep it quiet because it looks good to help absorb sounds so it can stay noisy The image represents which of the following wave interations

Reflection

Absorption

Transmission

Diffraction

What pattern best describes the relationship between wavelength and frequency

A. As frequency increases, wavelength increases

B. As frequency decreases, wavelength decreases

C. As frequency increases, wavelength decreases

D. There is no relationship between wavelength and frequency

Read the passage and then answer question

Stars and other objects in the universe give Off, or emit, energy in the form Of waves Most stars emit energy in all wavelengths. But how much Of each wavelength they emit depends on their temperatures. Hot stars emit mostly shorter waves with higher energy, such as X-rays, gamma rays, and ultraviolet waves. Cool Stars emit mostly longer waves with lower energy, such as infrared waves and radio waves. The Sun has a medium temperature range. It emits much Of its energy as visible light. These waves travel through vast regions of space and reach Earth

Which argument is best supported by the passage

The higher the temperature Of a Star, the more energy it emits

B. Cool stars do not produce radio waves

C. Visible light only comes from the Sun

D. The amplitude of a light wave is determined by its energy

#### Lesson 2: Reflection and mirrors

What happens when light reflects off a surface

Reflection of Light

When you look at a pane of glass, you sometimes can see an image of yourself. Light bounces off you, strikes the glass, and bounces back to your eye. Think about a calm lake like the one on the right. You can see the reflection of the trees on the other side of the lake

Law of Reflection

Light behaves in predictable ways when it reflects The rays in the ray diagram show how light reflects imaginarv line perpendicular to a reflecting surface is called the normal. The light ray moving toward the surface is the incident ray. The light ray moving away is the reflected r.y

law of reflection, when a wave is reflected from a surface, the angle of reflection is equal to the angle of incidence

An image that you can see, but does not really exist is called which of the following

A) Real Image

B) Fake Image

C) Virtual Image

D) Digital Image

4) a real image

A) is produced by virtual rays and can be projected on a screen

B) is produced by real rays and cannot be projected on a screen

C) is produced by virtual images and cannot be projected on a screen

D) is produced by real rays and can be projected on a screen

5) Convex lenses can produce

A) Real, erect images

B) Virtual, inverted images

C) Real, inverted images

D) no images form

6) Which describes a convex lens

A) triangular in shape

B) more transparent in the middle

C) thicker on the edges than in the middle

D) thicker in the middle than on the edges

Which lens is used to magnify objects and refract light. This type Of lens is curved outward

A) convex

B) concave

is a lens that is thicker in the middle and makes an object appear bigger

A) prism

B) convex lens

C) concave lens

D) mirror

is a lens that is thicker on its edges and makes an Object appear smaller

A) mirror

B) convex lens

C) concave lens

D) prism

What Does a Concave Lens DO

Make things bigger

Make things smaller

Make things closer

Make things happy

What Does a Convex Lens DO

Make things bigger

Make things smaller