Imagine the door to a theatre is opened and you are standing outside. how is it possible that you can hear the sound of the movie or play even if you cannot see the screen or stage ?

a) reflection only happens with sound waves not waves of light so the sound waves bounce out to your ears.

b) the sound waves refract as they move from one medium to another

c) the darkness in the theatre absorbed light but not sound so you can hear

d) the sound waves diffract much more than the light waves so try bend and spread as they move through the doorway.

What are the similarities & differences between a thermistor and a light dependent resistor in physics?

Which statements did both aristotle and ptolemy assume? check all that apply.

Lake happy times contains 100 km3 of pure water. it is fed by a river at a rate of 50 km3/yr. at time zero, there is a factory on one shore of lake happy times that begins introducing a pollutant to the lake at a rate of 2km3/yr. there is another river that is fed by lake happy times at a rate that keeps the volume of lake happy times constant. this means that the rate of flow from lake happy times into the outlet river is 52km3/yr. in turn, the flow from this outlet river goes into another lake, lake sad times, at an equal rate. finally, there is an outlet river from lake sad times flowing at a rate that keeps the volume of lake sad times at a constant 100 km3 . (a) find the amount of pollutant in lake sad times at the end of 3 months. (b) at the end of 3 months, observers close the factory due to environmental concerns and no further pollu- tant enters lake happy times. how long will it take for the pollutant in lake sad times (found in part (a)) to be cut in half?