Two convex lenses, each having a focal length of 10 cm , are positioned at a separation of 15 cm with their principal axes coinciding. What happens to a light beam coming parallel to the principal axis as it exits the lens system?

Step-by-step solution

For the first convex lens, the incident light beam is parallel to the principal axis. Therefore, the image is formed at its focal point. Using the lens formula for the first lens: u₁ = - f₁ = +10 cm v₁ = +10 cm This real image formed by the first lens acts as an object for the second lens. Since the distance between the lenses is 15 cm , the object distance for the second lens is: u₂ = -(15 cm - 10 cm ) = -5 cm Now, applying the lens formula for the second lens: 1 v₂ - 1 u₂ = 1 f₂ Substitute u₂ = -5 cm and f₂ = +10