# The focal length of a convex

Obviously these are not regular, plane mirrors. Imagine taking a giant ball and cutting a section out of it. You spray some shiny paint on the inside and outside and you have a curved mirror. The first kind we will be looking at is a concave mirror, which would mean that you made the inside of the ball shiny. Its principal focus is real. Its principle focus is virtual. It is thick in middle. It is thick at corners. It is thin at corners. It is thin at middle. Lens Terminology Principal Axis: Each of the two surfaces of a spherical lens is a section of a sphere.

The line passing through the two centers of curvatures of the lens is called principal axis. A point of the principal axis at the centre of lens is called optical centre.

The light rays travelling parallel to the principal axis of a convex lens after refraction meet at a point on the principal axis, called principal focus of focal point F.

## The Mirror Equation - Convex Mirrors

Hence,convex lens is also called converging lens. For a concave lens called principal focus F. Hence concave lens is also called diverging lens. This is the distance between the optical centre and the principal focus. Power of a lens Power of a lens is defined as the reciprocal of its focal length in metres.

Thus ,1 Dioptre is the power of a lens whose focal length is 1 meter. Because the focal length of a convex lens is positive,therefore,its power is also positive. Whereas the power of a concave lens is negative,for it has negative focal length. Image location by lens equation Let an object OP is placed in front of a convex lens at a distance p. A ray PR parallel to the principal axis after refraction passes through focus F. What is the size of image formed in a lens for a particular distance of object from the lens?General Science L Lab Lab 7: CONVEX LENS.

OBJECTIVE: To investigate the image formed by a certain thin convex lens and to determine its focal length. APPARATUS: Convex lens, optical bench, light source, target image slide, lens mounts, and screen. Focal length, usually represented in millimeters (mm), is the basic description of a photographic lens.

It is not a measurement of the actual length of a lens, but a calculation of an optical distance from the point where light rays converge to form a sharp image of an object to the digital sensor.

Feb 26,  · The percent deviation of focal length in convex lens 1 is % while in convex lens 2 is % which is within the acceptable range. The image formed when the concave and convex lens were not in contact was inverted and reduced and the calculated value of the focal length was mm.

Secure the 17cm and 50mm focal length convex lenses as shown below. 3. Build a rail system for each lens (see images below).

When you place the rail on the project board, you can adjust its position by sliding it along the rail. 4. To find the focal length of a given convex lens. Apparatus: Convex lens Metre rule Screen Candle Matches Wooden blocks Theory: In this experiment the focal length of a lens is found out.

The focal lens of a lens is the distance from the principal focus to the optical centre. It is the point where the image comes into focus when seen.

Focal length is the distance between a lens and its focal point, while the focal point is the point at which parallel light rays converge or diverge. Convex lenses have positive focal lengths.

Focal length - Wikipedia