Answer Happy

A person having normal eye sight sees a clear image without accomodating at infinity v He/she wants to use glasses to avoid any eye fatigue from accommodation when he/she reads a book at a distance of 40 cm. In order that the eye doesn't have to accommodate, the glasses must create an image of the book at an infinite distance. The book must therefore be placed in the front focal plane of the glasses. He/she has to choose converging glasses with a focal distance of mm (give an integer, pay attention to the change of units), i.e. with an optical power of diopters (give a decimal number with 2 significant figures).