please help asap no links
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[tex]\huge \mathcal\pink{Answer}[/tex]
So, Speed of light in Rock salt is 1/1.54 times speed of light in vacuum. Therefor Speed of light in Rock salt is less [1.94 x 10⁸m/s ] compared to speed of light in vacuum =C = 3 x 10⁸ m/s.