[单选题]
Diamonds are highly v
uasml x(vfg:g nd7-4w.6ydr u0l24p talued because
o p3a*l0 cofujv3l/ 2e of their sparkle. This is caused by total internal reflection, which reflects most of the light that falls onto a cut diamond out of the face we see. Fake gems, called 'paste', are often used in jewellery because they
pa*2e0 lcvo luf3oj3/ are cheaper. However, paste gems sparkle much less than real diamonds.
The diagrams show a possible path of light through a real diamond, and another through a fake.
If:
- $n=$ refractive index;
- $n_{d}$ is the refractive index of the diamond
- $n_{f}$ is the refractive index of the fake
- $v=$ speed of light
- $v_{d}$ is the speed of light in the diamond
- $v_{f}$ is the speed of light in the fake
Which row in the table contains only statements which must be true?
Post time 2024-1-26 22:03:40