I have an infinite number of glass blocks stacked side by side. The first block has refractive index n1, the second n2 and so on, such that n1<n2...<n(infinity). I shine a light on the stack, what angle does the ray make to the normal on the last block?

This question tests your knowledge of the behaviour of light through different mediums. We know that when light travels from air through glass, it tends towards the normal. This is because the glass is denser than air ie: n(glass)>n(air). Our glass blocks increase in density infinitely, so, applying our knowledge from earlier, we can say that the light will tend towards the normal until the infinitieth block where its path is on the normal, so the angle to the normal is 0 degrees.