(a(i))[2]
On Fig. 8.1, sketch a straight line to show a ray from the tip of the arrowhead of O to the tip of the arrowhead of I. Add a vertical dotted line to indicate where the lens is placed. This dotted line must extend above and below the principal axis.
(a(ii))[1]
Draw a second ray from the tip of object O to the tip of image I. This ray should pass through a principal focus. Mark the principal focus, F.
(a(iii))[1]
Work out the focal length of the lens.
(a(iv))[1]
State and explain one further characteristic of I.
(b)[1]
When it is full of water, the fishbowl may act as a converging lens. Suggest one hazard of leaving the fishbowl beside the window in bright sunlight.