Reflections, Rays, and Waves Study Set

A comprehensive set of practice questions covering the principles of reflection, refraction, diffraction, and wave calculations based on the Unit 4.04 and 4.05 lecture notes.

What is the definition of the Angle of Incidence?

The angle between an incoming wave, Ray or particle and the normal at the point Of Couston.

What is an Incident Ray?

A beam of light or radiation that strikes a surface, representing the initial/ Incoming path of the reflection/before reflection.

How is the Angle of Reflection defined?

The angle between the normal and the reflected ray.

What is a Reflected Ray?

The light ray that bounces off a surface after an incident ray strikes it.

What is the 'Normal' in the context of reflection?

The imaginary line perpendicular on a surface.

State the two components of the LAW OF REFLECTION.

1) Angle of incidence and angle of reflection are equal ($i=R$). 2) The incident ray, normal and reflected ray are all in the same plane.

What does the diffraction of light through a net curtain suggest about light waves?

It suggests that light waves have very short wavelengths because very small holes are needed to diffract light.

What is the definition of Diffraction?

Light waves bend round objects or spread through gaps.

What is an Image in the context of optics?

The reproduction of an object formed when light rays from a source converge or appear to diverge after reflecting off a mirror OR Refracting through a lens.

List the four PROPERTIES OF MIRROR IMAGE.

1) The image obtained is virtual. 2) The image is erect. 3) The size of the image is the same as the size of the object. 4) The distance between the image from the mirror is the same as the distance between the object from the mirror.

What happens when light passes through a narrow slit or around sharp edges?

It creates light and dark Fringe patterns rather than a shadow.

How do CDs (compact discs) demonstrate light diffraction?

The rainbow colours seen on the surface are caused by light diffracting off the tightly packed tracks.

What is Refraction?

The bending of light as it passes from one transparent material (or medium) into another, caused by light changing its speed when it enters a new substance.

Why does a swimming pool or pond always look shallower than it actually is?

Because of refraction; light bends when coming from the water into the air, and to the viewer, the rays seem to come from a point that is higher and closer.

How are Rainbows formed?

When sunlight passes through tiny water droplets in the air, the light bends and splits into all the different colours.

Why can sound waves NOT travel through a vacuum?

Sound waves can't be made if there is nothing/no material to squash and stretch.

What happens to a ray of light if it strikes a surface at a right angle (square-on)?

It goes straight through without being refracted.

Define 'triangular prism'.

A transparent optical element (like glass) with polished, flat surfaces that refracts and disperses light, typically separating it into a spectrum of colours.

What is 'dispersion'?

The effect where colours enter a prism together but are refracted (bent) different amounts by the glass.

State the wave equation formulas used to find wave speed, frequency, and wavelength.

$V = f \times \lambda$, where $V$ is wave speed ($m/s$), $f$ is frequency ($Hz$), and $\lambda$ is wavelength ($m$).

A wave travels at $18\,m/s$ with a wavelength of $6\,m$. What is its frequency?

$$f = \frac{V}{\lambda} = \frac{18}{6} = 3\,Hz$$

A wave has a frequency of $50\,Hz$ and a wavelength of $20\,cm$. Calculate the wave speed in $m/s$.

$$V = f \times \lambda = 50 \times 0.2 = 10\,m/s$$