By using a convex lens, a student obtained a sharp image of his classroom window grill on a screen. In which direction should he move the lens to focus a distant tree instead of the grill?
  1. Towards the screen.
  2. Away from the screen.
  3. Very far away from the screen.
  4. Behind the screen.

(a) Towards the screen.               


The distant tree can be considered as an object at infinity, and when the object is at infinity, the image is formed at the focus of the lens.

Converging Lens or Convex Lens -  It is a lens that possesses at least one surface that curves outwards. In other words, it is thick across the middle and thin at the upper and lower edges., because of which the light that enters the lens, get focused, or converged. Due to this effect, it is also called as a positive lens or a diverging lens.

The image formed by a convex lens is both real and virtual depending on the position of the object, which means both diminished and magnified images can be produced.


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