The physics textbooks use the definition of linear magnification (LM) in order to compare the size of the image with the object when addressing spherical mirrors and lenses. This work discusses the distortions generated by using the concept of LM and employs the angular magnification (AM) to show that the vision of the observer about to the relative size between the object and its associated image produced by concave spherical mirror depends on its own position. It was performed a qualitative analysis of two experiments, and even quantitative and graphics analysis of the modulus variation of AA as a function of the observer position for four types of images produced by a concave mirror. It is discussed the need of the introduction of the angular magnification concept in textbooks to understand the visualization of images formed by a concave spherical mirror.
physics teaching; concave mirror; angular magnification
