In order to start a fire, a camper turns a lens toward the sun to focus its rays on a piece of wood. the lens has a 12 cm focal length. use a ray diagram of the lens and the incoming light rays to find the distance from the lens at which the wood should be placed for the best effect.

F500 j of energy were added to 1 kg of each of these samples, which would experience the least temperature increase?

If the chemical properties of a substance remain unchanged and appearance or shape of a substance changes it is called a ?

The electric field between square plates of a parallel-plate capacitor has magnitude e. the potential across the plates is maintained with constant voltage by a battery as they are pulled apart to twice their original separation, which is small compared to the dimensions of the plates. the magnitude of the electric field between the plates is now equal to a)e b)e/4 c)e/2 d)4e e)2e