Light Energy and Electromagnetic Waves

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Questions and Answers

What happens to electrons when they absorb energy?

They move to a lower energy level.

They are ejected from the atom.

They jump to a higher energy level. (correct)

They release energy as heat.

What is the speed of light in a vacuum?

300,000 km/sec (correct)

600,000 km/sec

450,000 km/sec

150,000 km/sec

Which of the following best describes the concept of refraction?

Bending of light due to a change in speed. (correct)

Emission of light by hot objects.

Reflection of light off a smooth surface.

Absorption of light by a material.

What color is a completely opaque object that reflects red light?

Red Signup and view all the answers

What is the relationship between light frequency and wavelength?

Higher frequency correlates with shorter wavelength. Signup and view all the answers

Which of the following statements about transparent objects is correct?

They transmit light without scattering. Signup and view all the answers

What are photons?

Packages of energy released by electrons. Signup and view all the answers

In a primary rainbow, what color appears on the outer edge?

Red Signup and view all the answers

Which colors are classified as primary colors of light?

Red, blue, green Signup and view all the answers

What is the result of combining yellow and cyan pigments in digital media?

Black Signup and view all the answers

What do rods in the retina primarily detect?

Light and dark Signup and view all the answers

Which of the following statements best describes color blindness?

Difficulty in distinguishing between certain colors Signup and view all the answers

According to the law of reflection, what is true about the angle of incidence and the angle of reflection?

They are equal Signup and view all the answers

What occurs during diffraction?

Waves bend around the edges of a barrier Signup and view all the answers

What type of light is produced by heating an object until it glows?

Incandescent light Signup and view all the answers

Which secondary color is formed by mixing red and blue light?

Magenta Signup and view all the answers

Study Notes

Light Energy

Light energy is released when electrons fall to a lower energy level.
Atoms absorb energy, causing electrons to jump to a higher energy level.
Photons are bundles/packets of energy released during electron transitions.

Electromagnetic Waves

Light travels at 300,000 km/sec (or 186,000 mi/sec) in a vacuum.
Light travels slower in materials like air, water, and glass.

Light as a Transverse Wave

Light's energy is perpendicular to its direction of movement.
Moving photons create electric and magnetic fields.

Electromagnetic Spectrum

The visible spectrum is the portion of light we can see.
The colors of visible light are arranged from longest to shortest wavelength: Roy G. Biv (Red, Orange, Yellow, Green, Blue, Indigo, Violet).

Refraction of Light

Refraction is the bending of light due to a change in speed.
The index of refraction indicates how much a material refracts light.
Prisms bend light at different frequencies, separating it into different colors.

How We See

The lens in our eye refracts light, focusing it onto the retina.
Nerves transmit the image from the retina to the brain.
Rods are nerve cells sensitive to light and dark.
Cones are nerve cells that help us see color.

Color Blindness

Approximately 8% of men and 0.5% of women experience color blindness.
Color blindness is a problem with color receptors (cones). It causes an inability to distinguish certain colors, most notably red and green.

Reflection Diagram

The incident beam is the light striking a mirror.
The reflected beam is the light bouncing off a mirror.
The normal is a line perpendicular to the mirror's surface.
The angle of incidence equals the angle of reflection.

Law of Reflection

The angle of incidence is equal to the angle of reflection.

Diffraction

Diffraction is the bending of waves around the edge of a barrier.
New waves are formed from the original, creating bands of light and dark colors.

Sources of Light

Incandescent light is produced by heating an object until it glows.
Fluorescent light is produced by electron bombardment of gas molecules. Phosphors absorb photons—created when mercury gas gets zapped with electrons—to produce light.

Optical Instruments

Optical instruments include cameras, telescopes, microscopes, and lasers.

Lasers

Lasers are an acronym for Light Amplification by Stimulated Emission of Radiation
Lasers emit coherent light, meaning their waves are in phase. This makes them very powerful and intense, among many other uses.
Holography is a technique that uses lasers to create 3D images.
Fiber optics use light energy transmitted through long, flexible glass or plastic fibers. It's used in communications, medicine, television transmission, and data processing.

Color of Light

White light is the combination of all colors in the visible spectrum.
Black objects absorb all colors, reflecting none.
Transparent objects transmit light without scattering. The transmitted color is the color seen.
Translucent objects scatter and transmit some light.
Opaque objects either reflect or absorb light. The reflected color is the color seen.

Color of Light (Primary Colors)

Red, blue, and green are the primary colors of light. They can be combined to create any other color of light.

Color of Light (Additive Colors)

Secondary colors are made by combining two primary colors. Magenta, cyan, and yellow are secondary colors of light.

Paint Pigments

Paint pigments are colored substances that absorb or reflect light to give color to a substance.
Red, yellow, and blue are the primary pigments.
In digital media, mixing yellow, cyan, and magenta creates black.
Pigments are subtractive; when different colors are combined, they absorb more light, resulting in darker colors.

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Description

Explore the fascinating world of light energy, including how electrons transition between energy levels and the properties of light as a transverse wave. This quiz will cover various topics such as the electromagnetic spectrum and the refraction of light in different materials.