A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?

Which combination of matter shows almost no diffusion?

Bubbles of air coming out through water in glass vessel appears silvery to an observer standing by the sides Explain the reason.

Refractive index of a solid is observed to have the same value along all directions. Comment on the nature of this solid. Would it show cleavage property?

A hollow sphere filled with water is hung by a thread. If it has a small hole at the bottom through which water slowly goes out, how does the time period change ?

Take a table - tennis ball and make three slits into it. put semicircular fins cut out of a metal sheet into these slits. Pivot the tennis ball on an axle through its centre with a straight metal wire fixed to a rigid support. Now connect a cycle dynamo to this. connect a bulb in series. Direct a jet of water or steam produced in a pressure cooker at the fins. What do you observe ?

A man is standing on the deck of a ship which is 25m above water level. He observes the angles of elevation of the top of a lighthouse as 60° and the angle of depression of the base of light house as 45°.Calculate the height of the light house.

You are given kerosene, turpentine and water. In which of these does the light travel fastest? Use the information given in table.