Lens effects

 

Drag the lens to move.

Right click inside the lens to see the object without magnification.

 

Related applets:

Lens effect due to ripples


1. The lenses are not thin. They are

Convex 1 Spherical plano-convex lens with the curved surface upwards
Concex 2 Spherical plano-convex lens with the curved surface downwards
Concex 3 Cylindrical plano-convex lens with the curved surface upwards
Concex 4 Cylindrical plano-convex lens with the curved surface downwards
Concave 1 Spherical plano-concave lens with the curved surface upwards
Concave 2 Spherical plano-concave lens with the curved surface downwards
Concave 3 Cylindrical plano-concave lens with the curved surface upwards
Concave 4 Cylindrical plano-concave lens with the curved surface downwards
Prismatic 1 45-90-45 prism with hypotenuse upward and right angle at the right
Prismatic 2 45-90-45 prism with hypotenuse downward and right angle at the left

2. The lengths h and R in the ratio h/R are

3. The image is calculated on the assumption that the observer is far away from the lens and the background picture is put under and close to the lens.

4. This applet is written in full accord with Snell's law of refraction. The image seen through the lenses in this applet are perfectly identical to the real cases. Click here to see a comparsion.

5. If either the ratio h/R or the index of refraction, n,is too large, opague region(s) may appear at the edge of the lens.

Indeed, this phenomenon is very common.

Stand a transparent semi-circular block upright with its flat surface upwards. When viewed from the top, the two ends of the upper flat surface will not show the image of the bottom paper.

Practically, this can serve as an easy method of finding the index of refraction of the block.

Easy method of finding the index of refraction (pdf).

6. Use the mouse to drag the lens to move; right click inside the lens to see the background without magnification.