[list]Choose the refractive indices value by sliding the n[sub]1[/sub] and n[sub]2 [/sub]cursors. Choose the position of the object by dragging point u. Choose the curvature of the surface by dragging the blue dot on top of the grey curve (label X). The values ​​of the radius of curvature r, the object coordinate u, and the image coordinate v are presented.[/list]

[br]1. When is refraction on spherical surfaces convergent or divergent?[br]2. What kind of images are produced by divergent refractions? What about the convergent ones?[br]3. Can you verify the validity of the Refracting Surface Equation?[br]4. When is the secondary focus to the right of the refracting surface? When is it on the left? [br]5. What about the primary focus? [br]6. Are any foci located at the midpoint between the centre of curvature and the apex? [br]7. On which side of the surface are virtual images formed? What about the actual images? [br]8. Is it possible to form a real and upright image?