The Lens Laboratory
Drag the yellow object along the axis, change the focal length, and watch principal rays converge or diverge in real time.
30 cm
15 cm
8 cm
Through optical centre
Parallel to axis
Through focus
Project onto virtual screen
Tip: drag anywhere on the canvas to move the object. Scroll or pinch to zoom, shift-drag (or right-drag) to pan, and tap the home icon to reset the view.
Current case
At 2F₁
Image at 2F₂ · same size · real & inverted.
Terrestrial Telescope
Real
Inverted
same
Object distance
30 cm
Image distance
30.00 cm
Object height
8 cm
Image height
-8.00 cm
Magnification
-1.00
Focal length
15 cm
Lens formula
\(\dfrac{1}{v} - \dfrac{1}{u} = \dfrac{1}{f}\)\(\dfrac{1}{30.00} - \dfrac{1}{-30.00} = \dfrac{1}{15.00}\)Magnification
\(m = \dfrac{v}{u} = -1.00\)