PDF Overview of various methods for measuring a lens focal length 7. The percent deviation of focal length in convex lens 1 is 2.03% while in convex lens 2 is 0.87% which is within the acceptable range. Focal length - Wikipedia Two converging lenses of equal focal length, since the lens are diverging and they will cross. MP4-9, determine and report asf: , the expected focal length and the uncertainty in the focal length of this combi- nation of lenses used . Aim. The purpose of this experiment is to determine the focal length of a thin lens and to measure the magnification for a certain combination of object and image distances. By definition, the focal length . PDF Study of two-lens system with the method of Newton's lens formula That is, you hold the lens up near a screen and move it around until you get a crisp image of the landscape seen through the laboratory window, and the distance from the lens to the screen is is the focal length. Pop Up Procedure Simulation. A lens of focal length 20 cm forms the image of a bright object kept 30 cm from it on a screen. Apparatus Required: Two convex lenses of different focal length and an optical bench with four uprights; a lamp of narrow opening, a cross‐slit screen, nodal slide assembly and a plane mirror. focal length of combination of lenses experiment Focal lengths of converging and diverging lenses. A concave mirror has the focal length of 20 cm. Materials: • optical bench • lenses • object box • screen Preliminary Questions: 1) An object with a height of 2cm is placed at a distance d=20 cm in front of a converging lens with a focal distance f=5cm. 4. Mount the light source, the cross-arrow target and the viewing screen on the optical bench. Lenses should be so chosen so that the focal length of the combination should not be greater than 20 cm, e.g. Apparatus: A LED light as a point source, two convex lenses of known focal length and a concave lens of unknown focal length, graph paper and lens holders.