How we see things | Starter Quiz | Oak National Academy

Which of the following words is the opposite of ‘smooth’?

• bright

• rough

• shiny

• dark

Answer explanation

A smooth surface, such as a flat window pane, is not uneven – you cannot feel any bumps, dents or holes in it. The opposite of smooth is rough. A rough surface, such as velvet or concrete, is uneven.

Which of the following words is the opposite of ‘shiny’?

• sticky

• dark

• black

• dull

Answer explanation

The opposite of shiny is dull (or matt). A shiny surface, such as polished metal, is glossy. If you shine a torch beam onto it, it looks bright where the beam hits. A dull surface, such as cotton or rubber, looks less bright where light hits it.

Which of the following statements about light rays are correct?

• They are a way of modelling light.

• They point in the direction the light travels.

• A very thin beam of light can be made of only one ray.

Answer explanation

Light rays are a way of modelling light. They are not real, so light is not actually made up of rays. We can drawn rays in diagrams to show the direction light travels.

Tags

NGSS.MS-PS4-2

The first law of reflection states that the angle of reflection equals …

• the angle of incidence.

• a right angle.

• the incident ray.

• the reflected ray.

Answer explanation

The angle of reflection (the angle between the reflected ray and the normal) equals the angle of incidence (the angle between the incident ray and the normal).

Tags

NGSS.MS-PS4-2

The second law of reflection states that the incident ray and the reflected ray are …

• along the normal.

• on opposite sides of the normal.

• on the same side of the normal.

Answer explanation

The normal is an imaginary line drawn at 90° to the reflecting surface, meeting it at the point where the ray reflects. The second law of reflection states that the incident ray and the reflected ray are on opposite sides of the normal.

Tags

NGSS.MS-PS4-2

The third law of reflection states that the two rays and the normal are all …

• in different directions.

• along the same line.

• in the same plane.

• in different planes.

Answer explanation

When reflection happens, the incident ray, reflected ray and normal line are all in the same plane. That means they all run along one flat surface, which is why you can draw them all on a single flat piece of paper.

Tags

NGSS.MS-PS4-2