(a)[2]
Explain, using the behaviour of light rays, what principal focus means for a thin converging lens.
(b)[1]
State the meaning of focal length.
(c(i))[1]
Use the straight ray joining the tip of O to the tip of I to locate the lens position. Show the lens by drawing a vertical line labelled L from the top of the grid to the bottom.
(c(ii))[2]
On Fig. 5.1, construct a ray through one of the principal focuses and find the focal length of the lens.
(c(iii))[2]
On Fig. 5.3, place a tick in one box (☑) to show how the image on the translucent screen appears to an observer looking at the screen from point P. Explain why the image looks like this.