New servers, hooraaaay! More bandwidth, more power.
for igcse? here u go: http://www.astarmathsandphysics.com/igcse_physics_notes_menu.html there r some more refrences here gimme few min..
Am busy now trying to find a decent cheap car.
Never heard of an optic pin
The pins used for light experiments? 2 to 3 of them arranged on either side of the prism/glass block and later used to draw rays. TO my knowledge. Two are used a object. A prism is placed in front of them. The image of the two pins are spotted from the other side and two more pins are arranged in a straight line as seen.