the speed of light in vacuum is 3.0 x 108ms-1. If the refractive index of a transparent liquid is \(\frac{4}{3}\), then the speed of light in the liquid is
The hatch door of a submarine has an area of 0.5m2. The specific gravity of sea water is 1.03. Assume that g = 10ms-1,and neglect the atmospheric pressure. The force exerted by the sea water on the hatch door at a depth of 200m is