3d-Light and sound Flashcards
What type of waves are light waves?
A: Light waves are transverse waves, meaning the oscillations are perpendicular to the direction of wave travel.
What are the key properties of light waves?
A:
They can be reflected and refracted.
They travel at 3.0 × 10⁸ m/s in a vacuum.
They do not need a medium to travel (unlike sound waves).
What is the law of reflection?
A: The angle of incidence (i) is equal to the angle of reflection (r).
Oi= Or
How do you draw a ray diagram for reflection?A:
Draw the incident ray striking a reflective surface.
Draw the normal line (perpendicular to the surface).
Measure the angle of incidence (i).
Reflect the ray at the same angle (r) on the other side.
What is refraction?
A: Refraction occurs when a wave changes direction as it passes from one medium to another due to a change in speed.
How does light behave when moving between different media?
A:
From air to glass (more dense): Light slows down and bends towards the normal.
From glass to air (less dense): Light speeds up and bends away from the normal.
Practical: Investigating the Refraction of Light
Q: How can you investigate refraction using different blocks
Method
Method:
Shine a light ray at different angles and measure angles of incidence and refraction.
Record observations and draw ray diagrams.
Practical: Investigating the Refraction of Light
Q: How can you investigate refraction using different blocks?A:
Rectagular blocks
Rectangular Blocks: Measure how a ray bends at both entry and exit.
Practical: Investigating the Refraction of Light
Q: How can you investigate refraction using different blocks?A:
Semi-Cercular blocks
Semi-Circular Blocks: Observe refraction without reflection at the curved surface.
Practical: Investigating the Refraction of Light
Q: How can you investigate refraction using different blocks?A:
Triangular prism
Triangular Prisms: Investigate how light disperses into a spectrum.
What is the refractive index?
: The refractive index is a measure of how much light bends when entering a new medium.
Practical: Investigating the Refractive Index of Glass
Q: How can you determine the refractive index of glass?
A:
Place a glass block on paper and shine a light ray at an angle.
Mark the incident and refracted rays.
Measure and using a protractor.
Calculate using . Sin i / SIn r
Q: What is total internal reflection (TIR)?
A: Total internal reflection occurs when a wave hits a boundary at an angle greater than the critical angle and is completely reflected inside the medium.
Q: What is the critical angle (c)?A:
The critical angle is the angle of incidence above which total internal reflection occurs.
Formula for the critical angle:
c= i/ n
where is the critical angle and is the refractive index.
Q: How is total internal reflection used in optical fibres?A:
Light undergoes multiple total internal reflections inside a fibre.
Used in telecommunications (high-speed data transfer).
Also used in endoscopes for medical imaging.
