Language: English

# Get these flashcards, study & pass exams. For free! Even on iPhone/Android!

## Section 2.1 Light (22 Cards)

Light is a form of energy. (True or False)
True.
We see an object because our eyes are sensitive to . . . . . . . . . . .
light
Name a spectrum that light is part of.
electromagnetic spectrum
Light travels at . . . . . . . . . . m/s.
300,000,000 m/s
Sound travels at . . . . . . . . . .  m/s.
In a thunder storm do you hear thunder before you see lightning? (Yes or No)
No
In a thunder storm why do you see lightning before you hear thunder?
You see lightning before you hear thunder because light travels much faster (300,000,000 m/s) so it reaches your eyes before the sound from the thunder (330 m/s) reaches your ears.
Sound travels at 330 m/s. If you hear thunder 3 seconds after seeing the lighting, how far away is the thunder storm?
Light is a  . . . . . . . . . .  wave.
transverse wave
Draw and label a transverse wave.
An object that give off light is called . . . . . . . . . ?
luminous object
Explain how you see an object?
an object reflects light into your eyes
Why can't you see around corners?
because light travels in a straight line
Movement of light in a straight line is referred to as . . . . . . . . . ?
rectilinear propagation
Why can't you see through a brick wall?
because light cannot penetrate through a brick wall
If you cannot see through an object we say the object is . . . . . . . . . .
opaque
If you can see through an object we say the object is . . . . . . . . . .
transparent
If an object allow some light to go through we say the object is . . . . . . . . . .
Translucent
Which one of the following is a luminous object?
1) Comet
2) Sun
3) torch without batteries
Sun
Which one of the following has a sharp and clean shadow?
1) umbra
2) penumbra
umbra
Which one of the following has a fuzzy shadow?
1) umbra
2) penumbra
penumbra
Why is the umbra image sharp and clear?