SCIENCE CLASS 9 CHAPTER 1 MCQ
Q1When Heat Is Constantly Supplied By A Gas Burner With Small Flame To Melt Ice, Then The Temperature Of Ice During Melting:
[A]. Increases very slowly
[B]. Does not increase at all
[C]. First remains constant and then increases
[D]. Increases to form liquid water
Answer: Option B
Explanation:During melting, temperature of the ice does not change at all because the heat is used in overcoming the particle-particle attraction forces, which in turn keeps the temperature constant.
Q2
Which Of The Following Statement Is Or Are Incorrect?
[A]. The pollen grains move on the surface of water because they are constantly being hit by the fast-moving particles of water.
[B]. When a beam of Sunlight enters a room, we can see tiny dust particles suspended in air which are moving rapidly in a very haphazard way.
[C]. The zigzag movement of the small particles suspended in a liquid or gas is called Brownian motion.
[D]. The particles of matter do not attract each other.
Answer: Option D
Explanation:Explanation: The particles of matter attract each other. There are the characteristics of particles of matter.
Q3
Which One Of The Following Set Of Phenomena Would Increase On Raising The Temperature?
[A]. Diffusion, evaporation, compression of gases
[B]. Evaporation, compression of gases, solubility
[C]. Evaporation, diffusion, expansion of gases
[D]. Evaporation, solubility, diffusion, compression of gases
Answer: Option C
Explanation:The rates of evaporation, diffusion and expansion of gases increases due to increase in temperature because when temperature increases the kinetic energy of molecules increases, which breaks or weakens the interaction between the atoms and sets the molecules free.
Q4
The Boiling Points Of Diethyl Ether, Acetone And N-Butyl Alcohol Are 35°C, 56°C And 118°C Respectively. Which One Of The Following Correctly Represents Their Boiling Points In Kelvin Scale?
[A]. 306 K, 329 K, 391 K
[B]. 308 K, 329 K, 392 K
[C]. 308 K, 329 K, 391 K
[D]. 329 K, 392 K, 308 K
Answer: Option C
Explanation:The correct order of boiling points of diethyl ether, acetone and n-butyl alcohol in kelvin scale is 308 K, 329 K and 391 K, which can be explained as: Boiling point of diethyl ether = 35 degree Celsius + 273 = 308 K Boiling point of acetone = 56 degree Celsius + 273 = 329 K Boiling point of n-butyl alcohol = 118 degree Celsius + 273 = 391 K
Q5
Arun Is Doing His Homework Which Is Given By His Teacher. Would You Help Him To Choose The Incorrect Sentences?
[A]. Each potassium itself must be made up of millions of small particles which keep on spreading and imparting color to more and more of water.
[B]. When we light an incense stick in one corner of a room, its fragrance spread in the whole room quickly.
[C]. The best evidence that particles of matter are constantly moving comes from the studies of diffusion and Brownian motion.
[D]. When a few crystals of copper sulphate are placed at the bottom of a beaker containing water, then water in the whole beaker turns green slowly.
Answer: Option D
Explanation:When a few crystals of copper sulphate are placed at the bottom of a beaker containing water, then water in the whole beaker turns blue slowly.
Q6
When Water At 0°C Freezes To Form Ice At The Same Temperature Of 0°C, Then It:
[A]. Absorbs some heat
[B]. Releases some heat
[C]. Neither absorbs nor releases heat
[D]. Absorbs exactly 3.34 × 10 to the power 5 J/kg of heat
Answer: Option B
Explanation:At 0°C, water releases some heat to lower the speed of molecules, and when it is cool enough the molecules of water are fixed at one position and they start vibrating. Ultimately, the water molecules convert into ice (solid).
Q7
Gunja Is Completed Her Science Chapter Where She Wrote Some Statements. She Wants To Know Whether The Statements Are Correct Or Not? Gunja Wants To Take Help From You:
[A]. There are some forces of attraction between the particles of matter which bind them together.
[B]. The force of attraction is maximum in the particles of solid matter and minimum in the particles of gases matter.
[C]. A material which can flow easily and requires a vessel to keep it called fluid.
[D]. All the above
Answer: Option D
Explanation:Here, all the statements are correct. Hence, your answer will be option [D].
Q8
When Heat Is Constantly Supplied By A Burner To Boiling Water, Then The Temperature Of Water During Vaporization:
[A]. Rises very slowly
[B]. Rises rapidly until steam is produced
[C]. First rises and then becomes constant
[D]. Does not rise at all
Answer: Option D
Explanation:Temperature of the water during vaporisation does not change at all because the heat is used in overcoming particle-particle attraction forces, which in turn keeps the temperature constant.
Q9
Consider The Following Statements And Choose The Correct One(S):
[A]. The space between the particles are the minimum in solids, a little more in liquids and the maximum in gases.
[B]. The forces of attraction between the particles are the strongest in solids, less strong in liquids, and negligible in gases.
[C]. The movement of particles is the minimum in solids, more in liquids and maximum in gases.
[D]. All the above.
Answer: Option D
Explanation:Here, all the statements are correct. Hence, your answer will be option [D].
Q10
A Few Substances Are Arranged In The Increasing Order Of ‘Forces Of Attraction’ Between Their Particles. Which One Of The Following Represents A Correct Arrangement?
[A]. Water, air, wind
[B]. Air, sugar, oil
[C]. Oxygen, water, sugar
[D]. Salt, juice, air
Answer: Option C
Explanation:The correct order of increasing “force of attraction” between their particles is : Oxygen < Water < Sugar It is because the force of attraction increases in the order i.e. Gas < Liquid < Solid.
Q11
The Evaporation Of Water Increases Under The Following Conditions:
[A]. Increase in temperature, decrease in surface area
[B]. Increase in surface area, decrease in temperature
[C]. Increase in surface area, rise in temperature
[D]. Increase in temperature, increase in surface area, addition of common salt
Answer: Option C
Explanation:When surface area increases and temperature rises, evaporation of water increases because the area which is exposed to the outer atmosphere is more and increasing the temperature leads to increase in the kinetic energy, due to which rate of evaporation increases.
Q12
During Summer, Water Kept In An Earthen Pot Becomes Cool Because Of The Phenomenon Of
[A]. Diffusion
[B]. Transpiration
[C]. Osmosis
[D]. Evaporation
Answer: Option D
Explanation:During summer, water kept in an earthen pot becomes cool because of the phenomenon of evaporation. Earthen pot has a large number of tiny pores in its walls and some of the water molecules continuously keep seeping through these pores to outside the pot. This water evaporates continuously and take the latent heat required for vaporization from the remaining water. In this way, the remaining water loses heat and gets cooled. Note: i) Diffusion is the net spreading out movement of a substance from a region of high concentration to a region of low concentration and mixing of a substance with another substance due to motion of its particles. ii) Transpiration is the process of water movement through a plant and its evaporation from aerial parts such as leaves. iii) Osmosis is the process in which solvent molecules move from their higher concentration to their lower concentration through semi permeable membrane. iv) Evaporation is the process in which a liquid changes into vapour or gas even below its boiling point.
Q13
In A Quiz Competition, You Are Asked A Question Where You Have To Choose The Statement Which Is/ Are Correct?
[A]. Ammonia gas can be liquefied by applying high pressure and lowering the temperature.
[B]. Solid carbon dioxide is stored under less-high pressure.
[C]. The conversion of solid carbon dioxide into carbon dioxide gas is a change of state which is caused by the increase in pressure and decrease atmospheric temperature.
[D]. Whatever be the temperature at which evaporation take place, the latent heat of vaporization need not be supplied whenever a liquid change into vapour or gas.
Answer: Option A
Explanation:Ammonia gas can be liquefied by applying high pressure and lowering the temperature. In option [B]: Solid carbon dioxide is stored under high pressure. In option [C]: The conversion of solid carbon dioxide into carbon dioxide gas is a change of state which is caused by the decrease in pressure and increase atmospheric temperature. In option [D]: Whatever be the temperature at which evaporation take place, the latent heat of vaporization must be supplied whenever a liquid change into vapour or gas.
Q14
Which Of The Following Statement Is Incorrect?
[A]. The particles of matter are very, very small
[B]. The particles of matter attract one another
[C]. The particles of some of the matter are moving constantly
[D]. The particles of all the matter have spaces between them
Answer: Option C
Explanation:The statement that the particles of some forms of matter move constantly is incorrect because the particles of matter of all three states– solid, liquid and gas –are moving constantly. Although the particles of solids are fixed at their positions, they vibrate constantly.
Q15
When A Gas Jar Containing Colourless Air Is Kept Upside Down Over A Gas Jar Full Of Brown-Coloured Bromine Vapour, Then After Some Time, The Brown Colour Of Bromine Vapour Spreads Into The Upper Gas Jar Making Both The Gas Jars Appear Brown In Colour. Which Of The Following Conclusion Obtained From These Observations Is Incorrect?
[A]. Bromine vapour is made of tiny particles which are moving
[B]. Air is made up of tiny particles which are moving
[C]. The particles of bromine are moving but those of air are not moving
[D]. Even though bromine vapour is heavier that air, it can move up against gravity
Answer: Option C
Explanation:The statement that the particles of bromine are moving but those of air are not moving is incorrect because the particles of matter are constantly in motion. It appears as if the air molecules are not moving because air is colourless.
Q16
The Property To Flow Is Unique To Fluids. Which One Of The Following Statements Is Correct?
[A]. Only gases behave like fluids
[B]. Gases and solids behave like fluids
[C]. Gases and liquids behave like fluids
[D]. Only liquids are fluids
Answer: Option C
Explanation:Gases and liquids behave like fluids. Both gases and liquids tend to flow due to less force of attraction between their particle. Also, they required vessel to keep them. Solids do not flow. Note: Fluid means a material which can flow easily and requires a vessel to keep it.
Q17
Which Of The Following Represent The Suitable Conditions For The Liquefaction Of Gases?
[A]. Low temperature, low pressure
[B]. High temperature, low pressure
[C]. Low temperature, high pressure
[D]. High temperature, high pressure
Answer: Option C
Explanation:With the help of experiments it can be shown that at low temperature and high pressures, gases will liquefy. Because these factors affect the interaction force of molecules i.e. the molecules are able to establish a force of attraction between them on lowering the temperature and increasing pressure.
Q18
Pankush Appeared In Class Test But He Confused To Know The Correct Statement. Would You Help Him To Know That?
[A]. Perspiration or sweating is our body’s method of maintaining a constant temperature.
[B]. All the water on the earth does not get evaporated due to the high value of the latent heat of vaporization of water.
[C]. During hot summer days, water is usually kept in an earthen pot to keep it cool.
[D]. All the above
Answer: Option D
Explanation:Here, all the statements are correct. Hence, your answer will be option [D].
Q19
When A Gas Jar Full Of Air Is Placed Upside Down On A Gas Jar Full Of Bromine Vapors, The Red-Brown Vapors Of Bromine From The Lower Jar Go Upward Into The Jar Containing Air. In This Experiment:
[A]. Air is heavier than bromine
[B]. Both air and bromine have the same density
[C]. Bromine is heavier than air
[D]. Bromine cannot be heavier than air because it is going upwards against gravity
Answer: Option C
Explanation:The process occurring here is diffusion and it is unaffected by the mass. Therefore, bromine being heavier, mixes with the colorless air.
Q20
Pooja Is Writing Some Statements But She Confused To Know Whether The Statements Are Correct Or Not? If You Know The Answer To This Question, Then Tell Her:
[A]. The process of liquid changing into vapour or gas even below its boiling point is called evaporation.
[B]. The rate of evaporation increases on increasing the temperature of the liquid.
[C]. The rate of evaporation decreases on increasing the surface area of the liquid.
[D]. When the humidity of air is low then the rate of evaporation is high and water evaporates more easily.
Answer: Option C
Explanation:The rate of evaporation increases on increasing the surface area of the liquid.
Q21
Which One Of The Following Statements Is Not True?
[A]. The molecules in a solid vibrate about a fixed position
[B]. The molecules in a liquid are arranged in a regular pattern
[C]. The molecules in a gas exert negligibly small forces on each other, except during collisions
[D]. The molecules of a gas occupy all the space available
Answer: Option D
Explanation:The above answer is not true because in liquids the molecules are not arranged in regular pattern. In liquids the molecules are loosely arranged.
Q22
In The Last Year Board Examination, Rahul Were Asked A Question Where He Had To Choose The Statement Which Was/Were Correct? Will You Be Able To Answer This Question?
[A]. The temperature at which a solid substance melts and changes into a liquid at atmospheric pressure is called melting point of the substance.
[B]. When a solid is heated sufficiently it changes its physical state and becomes a liquid.
[C]. The melting point of a solid is a measure of the force of attraction between its particles as atoms or molecules.
[D]. All the above.
Answer: Option D
Explanation:Here, all these statements are correct. Hence, your answer will be option [D].
Q23
Anju Is Completed Her Science Chapter Where She Wrote Some Statements. She Wants To Know Whether The Statements Are Correct Or Not? Anju Wants To Take Help From You:
[A]. According to the kinetic theory of matter the particles of matter are in continuous motion and causes kinetic energy.
[B]. The spreading out and mixing of a substance with another substance due to the motion of its particles is called diffusion.
[C]. The rate of diffusion increases on increasing the temperature of the diffusing substance by heating.
[D]. The smell of perfume spreads due to the evaporation of perfume into air.
Q24
Read The Following Sentences Carefully, And Choose The Correct One:
[A]. The spreading of purple colour of potassium permanganate into water, on its own, is due to the diffusion of potassium permanganate particles into water.
[B]. The spreading of ink in water, on its own, is due to the diffusion of ink particle into water.
[C]. The diffusion of a solid substance into another solid substance is so slow that many people think that diffusion does not take place in solids.
[D]. All the above.
Answer: Option D
Explanation:Here, all these statements are correct. Hence, your answer will be option [D].
Q25
Puja Is Writing Some Statements But She Confused To Know Whether The Statements Are Correct Or Not? If You Know The Answer To This Question, Then Tell Her:
[A]. When a liquid freeze to form a solid an equal amount of heat is given out.
[B]. Ice at 0 degree Celsius is more effective in cooling a substance than water at 0 degree Celsius.
[C]. The latent heat of vaporization of water is 22.5 x 10 to the power 5 J/kg.
[D]. Once the water has begun to boil, the temperature gradually rises at hundred degree Celsius until all the water has changed into steam but many people thinks it remains constant.
Answer: Option D
Explanation:Once the water has begun to boil, the temperature remains constant at hundred degree Celsius until all the water has changed into steam.
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