When lisa placed a balloon to her ear, she was able to hear what her sister was whispering from the other side of the room. when she removed the balloon, she was no longer able to hear what her sister was saying. what is the best explanation for what lisa discovered?
a) the material from which the balloon is made makes sounds seem louder.
b) there is no air pressure inside the balloon, which makes sound waves travel more quickly.
c) the air in the balloon is not as dense as the air outside the balloon, which makes sound waves echo.
d) sound does not travel around the air outside of the balloon as well as it does through the denser air pressure inside the balloon.

What is required for an electric charge to flow through a wire? zero resistance in the wire a balance of electric potential high resistance in the wire a difference in electric potential

Antireflective coatings on solar cells are often made by applying a thin film of silicon nitride (sinx), which has an index of refractive of 1.2, on the top of the silicon solar cell, which has a refractive index of about 3.5. however, the sun emits radiation of various wavelengths which the solar cell absorbs, and the antireflective coating can only absolutely minimize the reflection of one of these wavelengths. the coating thickness is chosen to reduce the reflection of green/yellow light (e = 2.2 ev), which is the most intense color in the solar spectrum (shown below). which of the following coatings would minimize reflection of green/yellow light? the answer is 820 nm how? what is the angular width of the central maximum of an electron traveling at 2 x 108 m/s going through a single slit of width 1 mm.

Apersons beliefs and general outlook, which act like filters on the information they receive are called ?