老师,Q2B, 可以放因为 centre of gravity is higher, so it's unstable 和 area of the base is smaller 吗?
Q11b)ii) 可以放因为 when the light ray enters the optical fibre, it moves from a denser to a less dense medium ?
Question 5A 可以用 8cm 吗 ? 虽然是给了7cm可是我用了8cm。。。
还有 11 (ii)可以说因为 optical fibre is a denser medium as compared to air so since its a denser medium, total internal reflection occurs ?