The speed of light in an optical rare medium is more than an optically denser medium.
Hence, the given statement is true.
What happens if the ray of light goes from an optical rare medium to a denser medium?
When a ray of light travelling in an optically denser medium, emerges into an optically Iess denser medium, It:
Total Internal reflection happens only when light is travelling from an optically denser medium to an optically rarer medium.