NCERT Class – 9 Science Solution: Chapter 1 Matter in Our Surroundings-Part 3 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Question 13

Fill in the blanks:

(a) Evaporation of a liquid at room temperature leads to a ________ effect.

(b) At room temperature the forces of attraction between the particles of solid substances are ________ than those which exist in the gaseous state.

(c) The arrangement of particles is less ordered in the ________ state. However, there is no order in the ________ state.

(d) ________ is the change of gaseous state directly to solid state without going through the ________ state.

(e) The phenomenon of change of a liquid into the gaseous state at any temperature below its boiling point is called________.

Answer:

(a) Cooling

(b) Stronger

(c) Liquid, gaseous

(d) Sublimation, liquid

(e) Evaporation

Question 14

Match the physical quantities given in column A to their SI units given in column: B

SI Units
Physical quantitiesSI units
APressureiCubic metre
BTemperatureiiKilogram
CDensityiiiPascal
DMassivKelvin
EVolumevKilogram per cubic metre

Answer:

What is SI Unit

Question 15

The non SI and SI units of some physical quantities are given in column A and column B respectively. Match the units belonging to the same physical quantity:

SI and Non SI Units
Column AColumn B
ADegree CelsiusiKilogram
BCentimeteriiPascal
CGram per centimeter cubeiiiMetre
DBarivKelvin
EMilligramvKilogram per metre cube

Answer:

Question 16

‘Osmosis is a special kind of diffusion’ . Comment.

Answer:

  • Yes, this is true.
  • In both the phenomena, there is movement of particles from region of higher concentration to that of lower concentration.
  • However, in the case of osmosis the movement of solvent is through a semi permeable membrane which is permeable only to water molecules.
Osmosis