Light And Sound Flashcards
Are sound waves transverse or longitudinal
Longitudinal
Are sound waves mechanical
Need a substance to travel through
What do sound waves do to the ear drum and other solid parts of the human ear
Make them vibrate
Why is there a limit to the human hearing range
Conversion of sound waves in air to vibrations in ear only works over a limited range of frequencies
What’s the freuqeucy range of a normal human hearing
20 hz to 20,000 hz
What are ultrasound waves
Sound waves with a frequency above 20.000 hz
What happens to ultrasound waves when they meet a boundary between two substances
They are partially reflected and some are transmitted
What is echo sounding used for
Detecting objects in deep water, measuring the depth of water
What are the properties of p waves
Longitudinal, travels through liquids and solids
What are the properties of S waves
Transverse, can’t travel through liquids
Which observation suggests that the outer core of the earth must be liquid
S waves are not detected on the opposite side of earth
What’s the difference between concave and convex
Convex bulges out in the middle concave is thinner in the middle and thicker edges
What does a convex lens do to paralel rays of light
Light converges at the principal focus
What does a concave lens do to paralell rays of light
Light diverges so they appear to come from the principal focus
What is the focal length of a lens
Distance from the center of the lens to the principal focus
