Physics Year 8, Topic of Light

Revising for Light topic end of topic test

What is Snell’s Law?

Snell's Law: The Path of Light

Snell's Law (also known as the Law of Refraction) is a formula used to describe the relationship between the angles of incidence and refraction when light or other waves pass through a boundary between two different isotropic media, such as water, glass, or air.

Define Translucent

In physics and optics, translucent describes a material that allows light to pass through but scatters it in the process.

Unlike a transparent object, you cannot see clear images through a translucent one; instead, objects on the other side appear blurred, fuzzy, or indistinct.

Define Transparent

Transparent describes a material that allows light to pass through it with little to no scattering. Because the light waves travel through the material in a straight, predictable path, you can see clear, detailed images of objects on the other side.

In the world of physics, transparency occurs when the photons (light particles) do not interact strongly with the atoms of the material, allowing them to pass through the molecular "gaps."

Define Opaque

Opaque describes a material that does not allow any light to pass through it. Instead of transmitting light, an opaque object either reflects the light or absorbs it, converting that energy into heat.

Because no light travels through the material to reach your eyes, you cannot see anything on the other side.

Define Refract

The change in direction of a wave (such as light) as it passes from one medium to another with a different density. This occurs because the wave changes speed, causing it to bend at the boundary.

Define Luminous

Luminous: An object that generates and emits its own light through internal energy processes.

Define Non-Luminous

Non-luminous: An object that does not produce its own light. We only see these objects because they reflect light from a luminous source into our eyes.

Define Transmit

Transmit: The process by which a wave passes through a medium without being absorbed or reflected. For example, light transmits through clear glass.

Define Amplitude

Amplitude: The maximum displacement of a point on a wave from its equilibrium (rest) position. In light, higher amplitude corresponds to higher intensity or brightness; in sound, it corresponds to volume.

Define Wavelength

Wavelength: The distance between two successive identical points on a wave, such as from crest to crest or trough to trough. It is typically represented by the Greek letter lambda ($\lambda$).

Define Frequency

Frequency: The number of complete wave cycles that pass a fixed point in a given unit of time (usually one second). It is measured in Hertz (Hz).

Define Transparent

Passes straight through. Clear

Define Translucent

Passes through scattered. Blurry/Glow

Define Opaque

Blocked (Reflected/Absorbed) No visibility