Light : Chapter 3 - Section 1 Flashcards
True or False : Light does NOT require matter to travel through.
True.
What is light?
A type of energy that travels through waves.
True or False : Light is NOT an electromagnetic wave.
False. Light IS an electromagnetic wave.
True or False : Fields exist around certain objects.
True.
What is an electric field?
A field that surrounds every CHARGED object.
What is a magnetic field?
A field that surrounds every MAGNET.
What is radiation?
The transfer of energy as electromagnetic (EM) waves.
How can an EM wave be produced?
An EM wave can be produced by the vibration of an electrically charged particle. When the particle vibrates, the electric field around it also vibrates, and when the electric field starts vibrating, a vibrating magnetic field is created. The vibration of the electric and magnetic field together produces an electromagnetic wave.
What is the speed of light?
About 300,000 km/s.
True or False : Light travels FASTER in glass, air and other types of matter.
False. Light travels SLOWER in glass, air and other types of matter. Electromagnetic waves do not need a substance to travel through (unlike other types of waves) but they can travel through many types of matter.
About how long does it take for light to reach the Earth from the Sun?
About 8.3 minutes.
True or False : The Earth receives a large amount of light from the Sun, but only a small amount actually reaches the Earth.
True. The Sun sends out waves in all directions, so most of the EM waves sent to Earth by the Sun travel away into space.
True or False : The EM waves from the Sun are actually NOT the major source of energy on Earth.
False. The EM waves from the Sun ARE the major source of energy on Earth.
What process do plants use to store energy from the Sun?
Plants use a process called photosynthesis to store energy from the Sun.
True or False : Sound can travel around 880,000 times faster than light.
False. Light can travel around 880,000 times faster than sound.
