Light and Its Properties

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Questions and Answers

What unit is used to express light wavelength?

Millimeter

Angstrom (correct)

Centimeter

Decimeter

Which theory of light suggests that light is composed of small particles called corpuscles?

Quantum Theory

Wave Theory

Modified Wave Theory

Corpuscular Theory (correct)

What phenomenon occurs when light strikes a transparent medium and passes through?

Scattered

Reflected

Absorbed

Transmitted (correct)

What type of light is described as capable of exciting the human retina?

Visible Light Signup and view all the answers

What is the wavelength range of X-rays?

0.01 to 30 millimicrons Signup and view all the answers

Which types of light have wavelengths too short or too long to excite the retina of the human eye?

Invisible Lights Signup and view all the answers

What occurs when light hits a dark colored object, preventing it from bouncing or passing through?

Absorbed Signup and view all the answers

Who discovered X-rays, which are characterized by specific wavelengths?

Conrad Wilhelm Roentgen Signup and view all the answers

What is the wavelength range of visible light?

400 to 700 millimicrons Signup and view all the answers

Which primary colors are found in the visible spectrum?

Red, Green, Blue Signup and view all the answers

What characterizes an opaque object in terms of light?

Diverts or absorbs light and does not allow it to pass through Signup and view all the answers

What phenomenon occurs when light bends while passing from one medium to another?

Refraction Signup and view all the answers

Which of the following is a feature of transparent objects?

Transmits 90% or more of incident light Signup and view all the answers

What result occurs when an object appears red in color?

It reflects red and absorbs all other primary colors Signup and view all the answers

Isaac Newton demonstrated that white light is a mixture of what?

All colors of the spectrum Signup and view all the answers

Which type of light source is categorized as natural light?

Sunlight, moonlight, and starlight Signup and view all the answers

What type of sunlight does not cast shadows due to thick clouds?

Dull sunlight Signup and view all the answers

Which artificial light source is commonly used for general illumination rather than photography?

Fluorescent lamp Signup and view all the answers

What is the purpose of a reflector in a photoflood lamp?

To focus light onto an object Signup and view all the answers

Which type of light is described as coherent and aligned, often exemplified by laser light?

Coherent light Signup and view all the answers

What defines a flash bulb as a chemical lamp?

It generates light by chemical reaction Signup and view all the answers

Who is credited with inventing the hologram?

Dennis Gabor Signup and view all the answers

Which light source type is known for its high electrical consumption despite being widely used?

Incandescent bulb Signup and view all the answers

What characterizes blurry or unclear visibility in sunlight conditions?

Hazy sunlight Signup and view all the answers

What is a primary disadvantage of on-camera flash photography?

It can result in harsh shadows or red-eye effect. Signup and view all the answers

Which component of a camera is responsible for controlling the duration of light exposure?

Shutter Signup and view all the answers

What is the function of the film holder in a camera?

To hold the sensitized material securely in place. Signup and view all the answers

In terms of shutter speed, which of the following statements is correct?

Slow shutter speeds allow for brighter exposures. Signup and view all the answers

What is a key advantage of off-camera flash photography?

It allows for more control over light direction and quality. Signup and view all the answers

Which part of the camera is designed to gather and focus light to form an image?

Lens Signup and view all the answers

What is the purpose of the viewing system in a camera?

To show the entire scene coverage for recording. Signup and view all the answers

How does shutter speed relate to light gathering in photography?

Slower shutter speeds gather light more effectively than faster speeds. Signup and view all the answers

What is the primary function of using a fast shutter speed in photography?

To freeze the action of a subject. Signup and view all the answers

How does the focal plane shutter operate?

It uses a curtain mechanism to slide open and close. Signup and view all the answers

What does a lower f-number indicate about a lens aperture?

A larger lens opening and more light. Signup and view all the answers

What is the purpose of adjusting the diaphragm within a lens?

To control the amount of light that strikes the film. Signup and view all the answers

Which statement describes hyperfocal distance?

The closest distance that provides maximum depth of field. Signup and view all the answers

What happens when a photographer uses a smaller lens opening (higher f-number)?

Depth of field increases, allowing more objects in focus. Signup and view all the answers

What does the 'B' setting on a camera shutter do?

Keeps the shutter open until the photographer decides to close it. Signup and view all the answers

Depth of focus is best described as:

The range of distances where the film remains sharp. Signup and view all the answers

Study Notes

Light

Light is electromagnetic energy traveling as waves at 186,000 miles per second.
Wave Theory (Huygens): Light acts like waves, similar to a floating log moving up and down.
Corpuscular Theory (Newton): Light is made of tiny particles called corpuscles.
Modified Wave Theory (Maxwell and Hertz): Light is electromagnetic energy.
Quantum Theory (Einstein): Electrons in metal absorb light energy to escape.

Light Wavelength

The distance between two crests or troughs of light waves.
Measured in millimicrons (nanometers) or Angstroms.
One millimicron equals one-millionth of a millimeter.

Types of Light

Visible Lights: Wavelengths that can be seen by the human eye.
Invisible Lights: Wavelengths too short or long to be seen by the human eye.

Reflected, Transmitted, or Absorbed (RAT)

Reflected: Light bounces back when it hits a mirror.
Transmitted: Light passes through a transparent object, like glass.
Absorbed: Light is absorbed by dark objects, neither reflecting nor passing through.

Photographic Rays/Electromagnetic Spectrum

X-Ray: Wavelengths between 0.01 to 30 millimicrons, used in shadow photography.
Ultra-Violet Ray: Wavelengths of 30 to 400 nanometers, used for photographing fingerprints, documents, and invisible writing.
Visible Light: Wavelengths between 400 to 700 millimicrons, used for ordinary photography.
Infra-red: Wavelengths from 700 to 1000 millimicrons, used for photographing over-written documents, obliterated writing, and charred documents.

Colors of Light Found in the Visible Spectrum

Primary Colors: Blue, Green, Red
Secondary Colors: Cyan, Yellow, Magenta
Neutral Colors: Gray, White, Black
White: Presence of all colors.
Black: Absence of all colors.

Painted Objects

Reflect light, not produce their own light.
The color of an object is determined by the light it reflects.

Mediums of Light

Transparent Objects: Allow light to pass through, transmitting 90% or more of the incident light.
Translucent Objects: Allow some light through, transmitting 50% or less of the incident light.
Opaque Objects: Absorb most light, reflecting some.

Manner of Bending Light

Reflection: Light rebounding from a surface.
Refraction: Light bending when passing from one medium to another
Diffraction: Light bending when hitting the edge of an opaque object.

Light Source

Natural Light: Sources that exist without human intervention, like sunlight, moonlight, and starlight.
Artificial Light: Man-made sources like fluorescent bulbs, incandescent bulbs, and photoflood lamps.

Types of Natural Light

Bright Sunlight: Strong sunlight when clouds are absent.
Hazy Sunlight: Sunlight diffused by clouds, but objects still cast shadows.
Dull Sunlight: Thick clouds cover the sun, and objects in open spaces cast no shadows.
Cloudy Bright: Thick clouds cover the sun, but distant objects are visible.
Cloudy Dull: Thick clouds cover the sun, and distant objects are not easily visible.

Artificial Light

Continuous Radiation:
- Photoflood Lamp: Reflectorized light or spotlight, focused on the subject.
- Fluorescent Lamp: Tube lamps with fluorescent powder on their walls.
- Incandescent Bulb: Bulb with a wire filament that produces light when heated.
Short Duration:
- Flash Bulb: Chemical lamp that produces a burst of light.
- Concurrent Light: Light is scattered.
- Coherent Light: Light waves are aligned, like LASER light.

Hologram

Created using coherent light, especially laser light.
Invented by Dennis Gabor in 1948.

Flash Photography

Uses flash to illuminate subjects or scenes.
Flash can be built-in or externally attached.

Types of Flash Photography

On-Camera Flash Photography: Flash physically attached to the camera.
Off-Camera Flash Photography: Flash separated from the camera, allowing greater control over light direction and quality.

Camera

A light-tight box containing a light-gathering device and a mechanism to block unwanted light from reaching the sensitized material.

Essential Parts of a Camera

Light-Tight Box: Keeps light out and supports other components.
Lens: Collects and focuses light from the subject, forming an image on the film.
Shutter: Controls the duration of light exposure to the film.
Film Holder (Holder of the Sensitized Material): Holds the film in place, opposite the lens.
Viewfinder: Shows the photographer the scene coverage.

Other Parts of a Camera

Viewing System: Allows the photographer to see the scene they will capture.
Film Advancer (Film Advance Lever or Knob): Moves exposed film to the take-up spool and positions fresh film for the next exposure.
Shutter Speed: Regulates the amount of light that reaches the film.
Aperture: The size of the lens opening, controlling light intensity.
Diaphragm: A device within the lens that adjusts the aperture.
Depth of Field: The range of distance where objects appear sharp.
Depth of Focus: The distance a lens can be moved while keeping the subject in focus.
Hyperfocal Distance: The closest distance at which a lens can be focused to achieve maximum depth of field.
Focusing Mechanism: Controls the sharpness of the image by adjusting the lens position.

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Description

Explore the fascinating world of light, including its electromagnetic nature and different theories such as Wave Theory and Quantum Theory. Learn about the measurement of wavelengths and the classifications of visible and invisible light. Understand how light interacts with various surfaces through reflection, transmission, and absorption.