Saved Bookmarks
| 1. |
A lens is a piece of a transparent substance,bounded by two surfaces, out of which one must be curved. In a lens both the surfaces may also be curved. All the distances are measured from the optic centre.The direction of the incident ray is taken as positive and the direction opposite to the incident ray is taken as negative.The refraction formula for spherical curved surface isn2/v -n1/u = n2-n1/r andThe Gaussian formula for a lens is 1/v -1/u = 1/fImages of different sizes and nature are formed by these surfaces of the lens and they depend on the position of the object from the refracting surfaces.The power of a biconvex lens having the raidus of curvature |r1|= |r2| =40 cm of each surface and the refractive index of the material lens n = 3/2 will be(a) 2.5 D(b) 0.25 D(c) 25 D(d) 0.025 D |
|
Answer» Correct answer is (a) 2.5 D |
|