(a)[2]
Explain why the ray refracts and changes direction as it enters the glass.
(b(i))[2]
Explain what is meant by the principal focus (focal point) of a lens.
(b(ii))[1]
Explain what is meant by the focal length of a lens.
(c(i))[1]
On Fig. 4.2, draw an arrow to show the height and position of object O. The arrow should begin on the principal axis.
(c(ii))[3]
On Fig. 4.2, draw two rays from the tip of the arrow drawn in c(i) to find the position of the tip of the image I of object O. Draw an arrow to show the image I of object O. Label the image I.
(c(iii))[1]
State whether the image I of the object O is a real or a virtual image, and explain your answer.