study question
5. Explain the following:
(a) A very small amount of mercury on placing
over a clean glass plate forms a tiny spherical
ball.
(b) A very small amount of water on placing over
a clean glass plate forms an oval shaped
drop.
6. (a) What do you understand by the term
meniscus?
(b) Name the kind of meniscus formed (i) in case
of water, (ii) in case of mercury.
7. On the basis of kinetic model, explain how the
liquids exert pressure.
8. On the basis of kinetic model, explain how the
gases exert pressure.
9. Explain the heating of an iron rod by conduction
on the basis of kinetic model.
10. Liquids and gases get heated by convection.
Explain the convection on the basis of kinetic
model.
Answers
Answer:
5.
(a) Mercury has a much greater force of cohesion than its adhesive force with glass. ... therefore the molecules of mercury rearrange themselves so that no unbalance force acting upon the molecules of mercury.in doing so they take a spherical shape.
(b) A very small amount of water on placing over a clean glass plate forms an oval shaped drop. The force of attraction between the molecules of water, that is, the force of cohesion is far less than the force of adhesion between the molecules of water and the glass plate and hence it takes an oval shape.
6.
(a) The meniscus is a C-shaped piece of tough, rubbery cartilage that acts as a shock absorber between your shinbone and thighbone. ... Each of your knees has two C-shaped pieces of cartilage that act like a cushion between your shinbone and your thighbone (menisci).
(b) (1) Convex meniscus is formed.
(2) Mercury metal forms a convex meniscus in glass vessels.
7. All the liquids exert pressure on the base or bottom and walls of their container. All the liquid have weight. When we pour liquid into a vessel, then the weight of liquid pushes down on the base of the vessel producing a pressure. The liquid exerts pressure on the base of the vessel.
8. The particles of gas are constantly moving with a higher speed than solids or liquids. This enables a gas to exert more pressure on walls of any container through collisions of molecules of gas with molecules of the container. ... They collide with one another and also with the walls of vessel.
9. When an iron rod is heated from one end, its atoms gain heat energy at that end. This gain in heat energy increases the kinetic energy of the atoms. So the atoms vibrate more vigorously about their mean positions.
10. Convection happens in fluids (liquids & gases). The heat energy moves through the material as the particles in the material move through the material. Hot liquids and gases rise because when they are heated they expand and become less dense.