Chapter 5 : Ray Model of Light Flashcards
How do luminous objects allow us to see them?
They emit light in all directions. Light then travels in straight lines from these objects to our eyes. Thus, we are able to see the objects.
Define reflection.
It is the bouncing of light off a surface.
What is the surface of a plane mirror like?
It is smooth and flat.
How many characteristics of plane mirrors are there?
5
What are the 5 characteristics of images formed by plane mirrors?
- The image is the same size as the object.
- The image is upright
- The image is virtual ( the image is formed inside the mirror and thus is unable to be formed on a screen
- The image is laterally inverted (reverses right and left sides of an image)
- The distance between the object and the mirror is the same as the distance between the image and the mirror.
What are the five parts needed to form a ray model of light?
- Incident ray
- Reflected ray
- Normal
- Angle of incidence
- Angle of reflection
What is a special characteristic for the angle of incidence and reflection?
The angle of incidence is always equal to the angle of reflection.
What are the 2 types of curved mirrors?
Concave and Convex mirrors
Convex mirrors curve ______
outwards
Concave mirrors curve ______
inwards
What are the 3 characteristics of images formed by convex mirrors?
- The image is upright
- The image is virtual
- The image is diminished
Convex mirrors provide a _________________________________
a wider field of vision
When are convex mirrors commonly used?
They are commonly used when a large area needs to be seen.
What are the benefits of placing convex mirrors at road junctions?
They allow drivers to see around blind corners, giving them more time to respond to oncoming traffic.
What are the benefits of installing convex mirrors at the corner of some shops?
They allow shopkeepers to see a large area from a single location.
What are the benefits of using convex mirrors as rear and side view mirrors of cars?
They enable drivers to see a large area of the traffic behind them.
What are the 3 characteristics of images formed by concave mirrors?
- The image is upright
- The image is virtual
- The image is magnified
What are the benefits of using a concave mirror as a dentist mirror?
They allow dentists to examine the teeth closely.
What are the benefits of using a concave mirror as cosmetic mirror?
It forms a magnified image of our face, allowing us to shave or apply make-up more easily
What are the benefits of using concave mirrors in the headlights of a car?
They reflect the light from the bulbs in the headlights to form strong beams of light, thus lighting up the road ahead.
What are the benefits of placing a concave mirror at the base of a microscope?
It reflects light from the lamp of the microscope to a specimen, allowing us to view the magnified image of the specimen.
How is each light ray reflected when they fall on a smooth surface?
When parallel rays of light fall on a smooth surface, each ray is reflected in the same direction.
_____ images are formed when reflection on smooth surfaces occurs.
Clear
How is each light ray reflected when they fall on a rough surface?
When parallel rays of light fall on a rough surface, each ray is reflected in a different direction.
Why are we unable to see our reflection on rough surface?
Since rough surfaces scatter light, we are unable to see our reflection on a rough surface
Define refraction.
Refraction is the bending of light at the boundary between two different transparent mediums due to a change in the speed of light as it passes from one material into the other which is caused by optical density
What physical property does an optical medium have?
Optical density
What does optical density do?
It affects the speed at which light travels through the medium.
What does it mean if the refracted ray bends towards the normal?
It means that the optical medium that it is travelling through is denser than the first one.
What does it mean if the refracted ray bends away from the normal?
It means that the optical medium that it is travelling through in less dense than the first one.
What happens when the light ray enters the next optical medium perpendicularly?
There will be no bending of light as there is no angle of incidence, meaning that there is also no angle of refraction. However, the speed of light still decreases in the denser optical medium.
Refraction can make swimming pools appear ______ than they actually are
shallower
What colors are white light made up of?
Red, orange, yellow, green, blue, indigo, violet
Which color light bends the most?
Violet light.
Which color light bends the least?
Red light.
Define dispersion.
Dispersion is the splitting of white light into its component colors.
How can infrared radiation be used?
It can be used in healthcare.
What are the harmful effects of infrared radiation?
Overexposure to infrared radiation can harm us. Workers who have prolonged exposure to infrared radiation must wear goggles to protect their eyes. Infrared radiation trapped in the atmosphere contributes to climate change.
How can ultraviolet radiation be used?
We can use it disinfect medical equipment and it is also an environmentally friendly method.
What are the harmful effects of ultraviolet radiation?
Overexposure to UV radiation can harm our eyes and cause skin cancer.
Why do we need to apply sunscreen?
It helps to filter put UV radiation
How is visible light used?
Plants rely on the energy provided by visible light to make sugars using carbon dioxide and water through photosynthesis. Visible light also allows us to carry out our daily activities.
What are the harmful effects of visible light?
Visible light can cause chemical changes in some materials and can also cause light pollution.
What happens when visible light causes chemical changes in some materials?
It will result in the deterioration of their quality.
What happens when visible light causes light pollution?
Light pollution negatively impacts living things that depend on Earth’s cycle of day to carry out life-sustaining activities such as migration, reproduction, searching of food, sleeping and escaping from predators.
