A student places a transparent semicircular block on a sheet of paper and draws
around the block. She directs a ray of light at the centre of the flat edge of the block.
Figure 1 shows the path of the ray through the block.
Figure 1
incident ray
centre of the flat
edge of the block
transparent
semicircular block
emergent ray \ sheet of paper
[foya}(4] State why the emergent ray does not change direction as it leaves the block.
[1 mark]