Sec 1 Science Summaries - My Light Padlet v.2 by Melody Ching

Properties of Light

jonathanfong1000 — 2023-10-30 03:26:48 UTC

Light travels in a straight line, and it is a form of energy. It travels at a speed of 3 X 10⁸m/s in a vacuum. When light hits an object, it can be reflected or refracted.

Light is reflected when it hits an opaque object. Light is refracted when it enters a transparent medium of different density.

Ray and beam of light

jonathanfong1000 — 2023-10-30 03:38:02 UTC

A ray of light is indicated by a single straight line. A collective light ray is called a beam of light. Beam of lights can be one of the following:

Parallel Beam

Convergent Beam

Divergent Beam

Reflection of Light

jonathanfong1000 — 2023-10-30 03:39:18 UTC

Reflection of light being bounced off after hitting and opaque surface. Reflection enables us to see objects in our surroundings.

In reflection of light, there are:

Incident ray: Light ray coming towards the surface.
Reflected ray: Light ray bouncing off the surface.

The type of reflection is affected by the type of surface:

Regular reflection: When light rays are incident on a smooth surface, they are reflected in a regular manner.
Diffused reflection: When light rays are incident on a rough surface, they are reflected in a diffused manner.

chingmelody82 — 2023-10-30 03:48:54 UTC

chingmelody82 — 2023-10-30 03:49:00 UTC

chingmelody82 — 2023-10-30 03:49:05 UTC

Q17) C

Q18) D

chingmelody82 — 2023-10-30 03:49:13 UTC

chingmelody82 — 2023-10-30 03:49:19 UTC

chingmelody82 — 2023-10-30 03:49:32 UTC

chingmelody82 — 2023-10-30 03:49:38 UTC

ii) Toy 2

iii) No, as reflection of light cannot occur of a uneven surface

chingmelody82 — 2023-10-30 03:49:44 UTC

chingmelody82 — 2023-10-30 03:49:49 UTC

The Laws of reflection

jonathanfong1000 — 2023-10-30 03:49:51 UTC

The two laws of reflection are:

The angle of incidence will always equal the angle of reflection.
In a reflection diagram. the incident ray, reflected ray, and normal must lie in the same plane

chingmelody82 — 2023-10-30 03:49:57 UTC

20) B

21) C

chingmelody82 — 2023-10-30 03:50:03 UTC

chingmelody82 — 2023-10-30 03:50:09 UTC

i) The appearance of the alphabet is due to the person seeing the eye chart through a mirror.

ii) L, P, E, D

chingmelody82 — 2023-10-30 03:50:15 UTC

iii) The image is virtual

C)i) 60,20

chingmelody82 — 2023-10-30 03:50:25 UTC

ii) Light bends when passing through a medium of different densities

Images formed in a plane mirror

jonathanfong1000 — 2023-10-30 04:04:50 UTC

The formation of an image in a plane mirror is due to the reflection of light. When the light rays from an object are reflected by a mirror and enter our eyes, our brain 'perceives' that light travels in a straight line from the image in the mirror instead.

The image formed by a mirror is a virtual image, it cannot be captured on screen.

Constructing a Plane mirror image

jonathanfong1000 — 2023-10-30 04:08:50 UTC

Step 1: Identify the position of the object and the observer.
Step 2: Determine the location of the image. It should have an equal distance from the mirror as of the object from the mirror.
Step 3: Construct two diverging light rays from the image. Note that you should use dotted lines for virtual rays in the mirror.
Step 4: Using the laws of reflection, draw the incident rays from the object.

Applications of different types of mirrors

jonathanfong1000 — 2023-10-30 04:12:33 UTC

Plane mirror: It can function as a rear mirror or a periscope.
Convex mirror: Can be used for blind corners as it allows the user to see wider areas. It can also be used as a security camera.
Concave mirror: Can be used as dentist mirrors, and microscopes, as it allows the user to see a magnified image.

Refractive Index

jonathanfong1000 — 2023-10-30 04:17:12 UTC

Refractive index is a measure of the bending of a light ray when travelling from one medium to another. There will be more refraction in the following conditions:

Light traveling perpendicular to the boundary of the media, even if they have different densities
Light passing through two medias of the same density.

Refraction of Light

jonathanfong1000 — 2023-10-30 04:24:51 UTC

Refraction is the bending of light rays when they travel from one transparent medium to another transparent medium. The refraction is caused by a change in the speed of light rays when they travel in the media of different densities.

Refraction of light can only take place in transparent media such as air, water, vacuum, glass, and diamond. Light travels at different speeds, in different media:

In a less dense medium, the speed of light is faster.
In a denser medium. the speed of light is slower.

Light ray travelling between the boundaries of two different media affect its refraction.

From a optically less dense medium, to a optically more dense medium, the light ray bends towards the normal.
From a optically denser medium to a optically less dense medium, the light ray bends away from the normal.

Effect of Refraction, Apparent depth, and Real depth

jonathanfong1000 — 2023-10-30 04:30:16 UTC

Due to the refraction of light, an object underneath the water will look as if it is nearer to the surface than it really is.

Real depth is the actual position of the underwater object.
Apparent depth is the depth perceived by the observer due to refraction of light.

The apparent depth is less than the real depth in the effect of refraction.

Dispersion of White light

jonathanfong1000 — 2023-10-30 04:33:12 UTC

White light is composed of seven different color components. Each color component refracts at a different angle when passing through a glass prism, so white light will be dispersed by a prism and displays a spectrum of seven different color components. The splitting of white light is known as the dispersion of light. A spectrum of colors can be recombined by placing two prisms with their vertices and bases in opposite directions.

Primary and Secondary colors

jonathanfong1000 — 2023-11-01 02:55:22 UTC

White light can be produced by mixing three distinct color components called the primary colors of light. They are red, blue, and green. These colors cannot be reproduced by mixing other colors.

Secondary colors can be produced by mixing two of the three primary colors

Red + Green = Yellow

Red + Blue = Magenta

Blue + Green = Cyan

Seeing Colored objects

jonathanfong1000 — 2023-11-01 03:30:00 UTC

An object's color depends on the light that is being reflected to the observer. For example, a leaf will look green to an observer, as when the white light strikes the leaf, only the green light will be reflected. The green light will then enter the eyes of the observer, so the leaf will appear green.

Color Filter

jonathanfong1000 — 2023-11-01 06:01:56 UTC

A color filter is a type of glass or plastic sheet that only allows its own color component to go through.

For example, a when a beam of yellow light passes through a cyan filter, it will appear green, as the filter only lets the green part of yellow to pass through.