1. The problem statement, all variables and given/known data An optics lecturer bought his first multifocal eye glasses a while ago. The correction for looking far away was –2.25 diopters. Compared to this, the reading part had an additional correction of +1.75 diopters to achieve the convenient reading distance of 40 cm. He also bought for driving additional glasses with the same -2.25 diopter correction. Why did the lecturer end up in a great risk of getting a speeding ticket when using the driving glasses? In the car, the distance from the driver’s face to the dashboard is 60 cm? 2. Relevant equations D = 1/f , and (1/so)+(1/si) = 1/f 3. The attempt at a solution Ok, so the lecturer is using glasses with -2.25 diopters with addiotional correction of +1.75 diopters compared to -2.25 diopters. So correction for reading is -0.5 diopters. Using lens formula I can calculate the position of formed image: si = (-0.5 - 1/40cm)^-1 = 1.9047 cm. So the retina is 1.9047 cm behind eyeglasses. Lecturer uses -2.25 diopter correction while driving. If the dashboard is 60 cm from the lecturer's face the location of image of that dashboard is by using lens formula: si = (-2.25 - 1/60 cm)^-1 = 0.44 cm. So the image of that dasboard is formed in front of retina which causes myopia. That is why the lecturer can't see the dashboard correctly thus making it difficult to see the actual speed. Is my reasoning correct here?