Select the correct answer. Light rays from an object after passing through a convex lens form an Image at the focal point behind the lens (opposite side of the object). What
is the actual position of the object?

1. do the particles in the medium material move in the same direction of the wave or at opposite direction to the wave? explain your answer. 2. by inputting more energy into the wave, i.e a large shake of the spring, which wave property also increases? 3. are there forces of friction acting while a wave is passing through a medium?