A person suffers from hypermetropia (long sight). Use of a spectacle lens of power +3.0 D+3.0\text{ D}+3.0 D allows the person to just see clearly an object placed 20 cm20\text{ cm}20 cm away from the eye.
Explain why the unaided defective eye cannot form a clearly focused image of the object placed 20 cm20\text{ cm}20 cm from the eye.
An object is placed 20 cm20\text{ cm}20 cm from the spectacle lens. Calculate the distance of the image formed from the spectacle lens. Give your answer to a suitable number of significant figures.
State the name for the position where the image is formed by the spectacle lens.
11 exam-style questions on AQA A Level Physics Physics of the eye (A-level only), covering Physics of vision (A-level only) and Defects of vision and their correction using lenses (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.