(a(i))[1]
On Fig. 3.1, draw a line connecting S and R and carry it on until it meets the block.
(a(ii))[1]
On Fig. 3.1, draw a line to finish the path of ray 1 through the block.
(b)[1]
On Fig. 3.1, complete the route of ray 2.
(c(i))[1]
Extend lines SR and XW backwards until they meet, then label the meeting point F.
(c(ii))[1]
Measure the perpendicular distance from F to the centre of the block. distance = ............................................. cm