Optics in 8th Grade

What is reflection?

• Reflection is the change in direction of a wave when it bounces off a surface

• Reflection is the absorption of light by a surface

• Reflection is the emission of light from a source

• Reflection is the bending of light around an object

Answer explanation

Reflection is the change in direction of a wavefront at an interface between two different media.

Tags

NGSS.MS-PS4-2

Explain the difference between concave and convex mirrors.

• Concave mirrors are flat, while convex mirrors are curved.

• Concave mirrors converge light rays, while convex mirrors diverge light rays.

• Concave mirrors reflect light rays, while convex mirrors absorb light rays.

• Concave mirrors diverge light rays, while convex mirrors converge light rays.

Tags

NGSS.MS-PS4-2

How does refraction occur?

• Refraction occurs when light waves travel in a straight line

• Refraction occurs when light waves reflect off a surface

• Refraction occurs when light waves pass from one medium to another at an angle, causing the light to change speed and bend.

• Refraction occurs due to the absorption of light by a medium

Answer explanation

Refraction occurs when light waves pass from one medium to another at an angle, causing the light to change speed and bend.

Tags

NGSS.MS-PS4-2

Describe the role of lenses in optics.

• Lenses in optics are used for magnifying objects

• Lenses in optics are primarily used for color correction

• Lenses in optics have no impact on the behavior of light

• Lenses in optics bend and focus light rays, converging or diverging them to form images in optical instruments.

Answer explanation

Lenses in optics bend and focus light rays, converging or diverging them to form images in optical instruments.

What type of image is formed by a concave mirror when the object is placed close?

• Inverted and real image

• Enlarged and virtual image

• Inverted and virtual image

• Upright and virtual image

Answer explanation

Concave mirrors form an inverted and real image when the object is placed beyond the focal point.

Give an example of an everyday use of a concave mirror.

• Car side mirrors

• Telescopes

• Makeup mirrors

• Flashlights

Answer explanation

Makeup mirrors are an everyday use of concave mirrors as they magnify the reflection for better application of makeup.

Tags

NGSS.MS-PS4-2

In which direction does light bend when passing from air to water?

• Light bends away from the normal line.

• Light bends in a straight line.

• Light bends towards the normal line.

• Light bends in a zigzag pattern.

Tags

NGSS.MS-PS4-2

What type of lens is used to correct farsightedness?

• Concave lens

• Diverging lens

• Convex lens

• Flat lens

Identify the type of mirror commonly used in makeup mirrors.

• Flat mirror

• Convex mirror

• Plane mirror

• Concave mirror

Answer explanation

Makeup mirrors commonly use concave mirrors to magnify the reflection for better visibility during application.

Tags

NGSS.MS-PS4-2

Predict the path of light when it passes through a convex lens.

• The path of light through a convex lens diverges away from a focal point.

• The path of light through a convex lens remains straight.

• The path of light through a convex lens converges towards a focal point.

• The path of light through a convex lens forms a perfect circle.

Answer explanation

The path of light through a convex lens converges towards a focal point.

Tags

NGSS.MS-PS4-1

NGSS.MS-PS4-2