Intensity Problem set

Question 1
A droplet of water in a pond converts 1 J of potential energy to kinetic energy in half a second. A duck 50 cm away experiences this. What intensity of the wave does the duck experience? How far would the duck have to move from the source to ensure that the sound intensity dropped to 1 Wm-2?

Continue reading


Archimedes Death Ray

300px-Archimedes_Heat_Ray_conceptual_diagram.svg“The 2nd century AD author Lucian wrote that during the Siege of Syracuse (c.214–212 BC), Archimedes destroyed enemy ships with fire. Centuries later,Anthemius of Tralles mentions burning-glasses as Archimedes’ weapon.[30] The device, sometimes called the “Archimedes heat ray”, was used to focus sunlight onto approaching ships, causing them to catch fire.” From Wikipedia

Continue reading