• Lens Maker's formula () ... • Note simple lens formula assumes tc = 0 which is never true • But if f is large then r’s large and tc is small so good approximation • Note plano-convex r2 = ∞ and fthin = fthick but principal point changes . A magnifying glass consists of a converging lens of focal length 25 cm. It might be useful to solve the lens equation algebraically for each of the parameters: 11 1. pqf qp f qp qf p qf pf q p f Example 3. A lens has two foci, F and , on either side of it by the sign convention. The point where image of an object placed at infinity is formed is called the focus (F) of the lens and the distance f gives its focal length. Equation (v) is known as the lens makers formula. Section 2: The Lens Equation 10 The ray diagram is drawn using the two rules fromp. Want to read all 3 pages? See also: Lens, Thin Lens Formula . Thick Lens Formula : The above figure is Figure 2.5, p. 13, from Schroeder (1987). You've reached the end of your free preview. BC1 = R 1 CD2 = R 2 Therefore, equation (iv) can be written as. What are the nature, size, and location of the image? 11 1. p qf (15 cm)(25 cm) 15 cm - 25 cm. The image is also upright. Using the positive optical sign convention, the lens maker's formula states {1\over f} = (n-1)\left({{1\over R_1} - {1\over R_2}}\right) where f is the focal length, n is the index of refraction, and R_1 and R_2 are the radii of curvature of the two sides of the lens. Example 3. A bug is 8 mm long and placed 15 cm from the lens. F F p = 15 cm; f = 25 cm. Derivation of General Form of Lensmaker Equation.pdf - Derivation of General Form of Lensmaker Equation.pdf - School Diablo Valley College; Course Title PHYS 231; Uploaded By koye123456789. This is the signi cance of v, the image position, being negative. F v= 8cm u= 4cm We see that the image is on the same side of the lens as the object! Derive the formula where s = distance of object from lens s' = distance of image from lens f = focal length of the lens. This video is highly rated by Class 10 students and has been viewed 13 times. It is also evident that the light rays only appear to pass through the position of the image. Derivation of Lensmaker’s formula. Applying the equation of paraxial refraction with (air) to each surface gives (1) (2) Using , (3) Adding (1) and (3) gives (4) For conjugate points, (5) As is derived by Morgan, (6) The ends of the lens are at (7) (8) Morgan, J. This preview shows page 1 - 3 out of 3 pages. 5. Nov 10, 2020 - Derivation of Lens Maker Formula Class 10 Video | EduRev is made by best teachers of Class 10. Introduction to Geometrical and Physical Optics. Pages 3. Derivation.