Science Exam Chapter 4: Light

Question 1

Refraction

Answer 1

The bending of light as it passes from one medium to another due to a change in speed.

Question 2

Refraction properties

Answer 2

*when light travels from a less dense medium to a more dense medium, it bends towards the normal.

*When light travels from a more dense medium to a less dense medium, it bends away from the normal.

Question 3

high/low refractive index

Answer 3

• Light bends towards the normal when entering a substance of higher refractive index.
• Light travels away from the normal when traveling to a substance with a lower refractive index.

Question 4

Total internal refraction

Answer 4

*When light enters a substance of lower refractive index. Eg glass to air it refracts away from the normal

• At the critical angle light refracts so
  far that it runs along the edge of the
  substance.

Any angle of incidence greater than
this, there is no refraction, only total
internal reflection

Question 5

Diffuse Reflection

Answer 5

• Occurs on rough surfaces.

*Light is scattered in many directions.

*Example: Reflection off a wall.

Question 6

Regular Reflection

Answer 6

*Occurs on smooth surfaces like mirrors.

*Light reflects at a single angle.

*Example: Reflection off a mirror.

Question 7

Law of Reflection

Answer 7

The angle of incidence ( 𝜃 𝑖) equals the angle of reflection ( 𝜃 𝑟).

Question 8

Characteristics of Plane Mirror Images

Answer 8

• Lateral Inversion: The image is flipped horizontally.

*Same Size: The image is the same size as the object.

*Upright: The image is upright (not inverted).

*Distance: The image appears to be the same distance behind the mirror as the object is in front.

Question 9

Luminous and Non-Luminous

Answer 9

Luminous Objects:
*Emit their own light.
*Examples: The Sun, light bulbs, fireflies.

Non-Luminous Objects:
* Do not emit light but can reflect light from other sources.
* Examples: The Moon, books, trees.

Question 10

Transparent Materials

Answer 10

• Allow light to pass through with minimal scattering.
• Objects can be seen clearly through them.

*Examples: Clear glass, clean water.

Question 11

Electromagnetic Wave Properties

Answer 11

• Light is an electromagnetic wave with wave-particle duality.
• Part of the electromagnetic spectrum, including visible light.
• Characterized by wavelength, frequency, and speed.

Question 12

Convex Lenses

Answer 12

Converge light rays, thicker in the middle, focal point where rays meet.

Question 13

Concave Lenses

Answer 13

Diverge light rays, thinner in the middle, focal point from which rays appear to diverge.

Question 14

Eye Parts and Functions