Grade 11 physics
Lenses and Optical Instruments; Spectral Apparatus
Lenses form images by refraction, while microscopes, telescopes and spectrometers combine optical elements to control angular size, resolution and wavelength separation.
1. Core ideas and learning goals
- For a thin lens, object distance, image distance and focal length satisfy 1/f = 1/do + 1/di under one sign convention.
- Linear magnification gives image size and orientation through m = -di/do.
- A microscope increases the angular size of a nearby small object using an objective and eyepiece.
- A telescope collects light and increases angular detail of distant objects; aperture affects brightness and diffraction-limited resolution.
- A prism or diffraction grating separates wavelengths, and a spectrometer measures their angles or positions.
2. Physical model
Lenses form images by refraction, while microscopes, telescopes and spectrometers combine optical elements to control angular size, resolution and wavelength separation.
Lenses form images by refraction, while microscopes, telescopes and spectrometers combine optical elements to control angular size, resolution and wavelength separation. The model links observable changes with measurable physical quantities and conservation laws.
Before applying a relation, specify the reference frame, system boundary, initial state and approximations. The conclusion is valid only while those conditions are satisfied.