Physics unit 3

An optical bench uses a thin converging lens of focal length f = 12 cm. For a real object and a real image, object distance u and image distance v satisfy 1/f = 1/u + 1/v. The magnitude of image magnification is M = v/u. A sensor is initially placed 24 cm behind the lens and a luminous square object is 24 cm in front. A circular aperture limits collected light. At fixed object position, the light power reaching the image is proportional to aperture diameter squared. For this experiment, mean image irradiance equals collected power divided by image area. Diffraction produces a blur diameter proportional to v/D, where D is aperture diameter. Geometrical defocus and diffraction are separate effects.