Explore topic-wise InterviewSolutions in Current Affairs.

Various properties of water are as follows:

1. It is a fluid substance because it can flow. 

2. It does not have its own shape, it takes the shape of a container in which it is kept. 

3. It has a definite volume. 

4. It is a transparent liquid and it has no colour. 

5. It is tasteless and odourless. 

6. It is a universal solvent.

i. mixture

ii. same

iii. Barometer

iv. decreases

v. increases, decreases

1. Air is made of oxygen, nitrogen, carbondioxide, water vapour and dust particles. 

2. All these are in different proportions. Therefore air is a mixture.

i. Wind

ii. humidity

iii. less

iv. medium

v. fluid

Water is a universal solvent. It dissolves more substances than any other liquid so there is no alternative to water for cleaning purposes.

• Diagram (a): Water is filled in the crack.
• Diagram (b): Water in the crack turns to ice due to decrease in temperature. When it turns to ice the volume increases and it expands. Due to expansion, the size of crack widens more than in diagram (a).

On filling air in balloon, the shape of the balloon changes. Its size increases due to expansion.

Following are the steps we suggest to reduce energy consumption:

1. We could develop the technology to use the available or known sources of energy more efficiently and also look to new sources of energy.

2. The fossil fuels are non-renewable sources of energy. So we need to conserve them.

3. We should encourage bio-gas instead cutting number of trees in the forest. Bio-gas is renewable source of energy.

1. Water dissolves more substances than any other liquid. It dissolves solids, other liquids and even gases in it. Therefore, it is called as Universal solvent. 

2. Water is used as a solvent in factories, laboratories, foodstuffs and in various types of biological processes occurring in the body such as digestion, excretion, etc.

i. 5^th December

ii. dew

iii. 101400

iv. Daniel Bernoulli

v. Scattering

vi. Sandy

1. The potato will sink in water as potato’s density is more than water.

2. This is the effect of density. The potato will float in salt solution as the density of salt solution is more than potato. The density of the water becomes greater due to the dissolved salt. That is why it is easier to swim in sea than in a well or a lake.

i. solvent

ii. silicon dioxide (quartz)

iii. clay

iv. Terracotta

v. Multani

Steps for reducing the energy consumption:- 

(i) Switch off all the lights, fans, TV and other appliances when not needed. 

(ii) Use of biogas as cooking fuel should be encouraged. 

(iii) Bicycles should be used for short distances to save precious fuels like petrol. 

(iv) Solar cookers should be used to cook food.

There are 3 types of soil on the basis of its texture.

1. Sandy soil: (a) Large particles are high in sandy soil, (b) Water drains rapidly through sandy soil, (c) It is easy to plough this soil, (d) It is less fertile because the particles of sandy soil are made of the mineral called silicon dioxide (quartz), (e) These particles do not dissolve in water and therefore the soil has very little capacity to supply dissolved nutrients. 

2. Silt soil: (a) The particles of silt soil are of medium size, (b) Silt soil is not as ploughable as sandy soil but is much more ploughable than clay soil, (c) This soil contains a large proportion of organic materials,

(d) Its capacity to supply nutrients is much greater, (e) Silt soil is also called sedimentary soil.

3. Clay soil: (a) The proportion of small particles is maximum, (b) The particles of clay soil feel smooth to touch, (c) Clay soil has a high water holding capacity.

1. Due to the ice cubes in the glass, the air surrounding the glass cools down. 

2. As the water vapour in this air cools down, it condenses and gets transformed into water. 

3. It is this water that collects on the outer surface of the glass.

Bernoulli’s principle is that the pressure of air ‘ decreases when its velocity increases while the pressure of air increases when its velocity decreases.

1. On pulling the piston of a syringe with the inlet hole of the syringe closed, more space becomes available to the air in the syringe, and it becomes rarified. 

2. As a result, the pressure of the air in the syringe is lowered. 

3. Comparatively the pressure of the outside air is very high. So when the pulled out piston is A released, it is immediately pushed in.

B) Liquids are not compressible

Correct option is C) gases

D) All the above

A) Effect of temperature on change of state

Correct option is B) NH₃, HCl 

Correct option is C) fluids

Correct option is A) liquid

Yes. The substance which can be found in three states like water is wax.

C) Remains constant

This statement is true. 

Reason: When sugar is dissolved in water, the particles of sugar occupy the space between the particles of water. Hence there is no change in the volume of water.

Conditions for observing the change in volume of water:

If we go on adding sugar without increasing the quantity of water, there will be no space between water particles, to be occupied by sugar particles. Hence the sugar remains undissolved.

(1) Force of attraction between the particles of the chalk is weak. 

(2) It is easy to break, but we can’t join. 

(3) To join two materials we need to let the molecules of two get near enough for the coulomb forces to start acting. 

(4) That’s why any solid keeps its shape. 

(5) Liquids can’t keep its shape because the molecular distance in liquids is too large for this action.

(1) Space between the particles of gaseous substance is more than solids and liquids. 

(2) In making of soda water, if we pass CO₂ into water it diffuses fastly. 

(3) When we try to mix two liquids they also diffuses fastly but when compared to gas to liquid, it take more time to diffuse. 

(4) If we try to dissolve sugar or salt in water they will take more time to diffuse because the space between particles is very less in solid state substance. 

(5) So we can conclude that space between gas to liquid particles is more and take more time to diffuse and space between the two liquids particles is more so, they will diffuse speedly.

(1) take a beaker and fill it with some water and mark the water level. 

(2) Add some salt and stir it thoroughly with a glass rod. 

(3) When all the salt has dissolved, we get a salt solution. 

(4) Observe the level of salt solution in the beaker. We will find that the level of salt solution in the beaker is at the same mark where water level was initially in the beaker. 

(5) From this activity, we can conclude that both the solid and liquid particles have some space between them and the solid particles enter into the space between the liquid particles whene we dissolves them in liquids

B) Measuring jar

1. Take a beaker and fill it with ice cubes. 

2. Find the mass (m₁) of the beaker along with ice cubes using a spring balance. 

3. Keep the beaker at rest for some time, till the ice changes into water. 

4. Then find the mass (m₂) of the beaker along with water. 

5. We observe that m₁ = m₂. 

6. We conclude that the mass never changes when a substance changes its state.

The volume of gas can be decreased by applying pressure. This process is called compression.

In gas leaked from gas cylinder speed of diffusion is more.

All substances cannot change from solid to liquid and liquid to gas on heating.

e.g.:

1. When wood is heated, it cannot change its state from solid to liquid, but the form of substance changes. 

2. Mercury/blood.

Correct option is B) fusion

(1) Diffusion depends on both material that is diffusing and the material it is diffusing through. 

(2) At certain temperature, all particles have the same average energy. 

(3) This means that lighter atoms, such as hydrogen, carbon, oxygen and nitrogen travel faster and are more mobile than larger atoms such as copper or iron. 

(4) Materials made of these lighter atoms diffuse faster than heavier materials.

The substances which can flow from one place to other place are called fluids. Generally liquids and gases are fluids.

Correct option is C) energy

Correct option is A) more

B) move continuously

C) In gaseous state

B) melting point

The mode of nutrition in which organisms make food by themselves is called autotrophic nutrition.

Anything in this world that occupies space and has mass is considered as matter. Examples: The water we drink, our food, clothes, chairs, tables, air we breath, etc. are the examples of matter.

Correct option is C) gas

A) 0°C to 4°C

1. Take a beaker full of water. 

2. Add a few crystals of potassium permanganate to it. 

3. We observe that the diffusion of potassium permanganate crystal into water and the colour of water changes. 

4. Repeat the experiment with crystals of copper sulphate. 

5. Here also we observe the diffusion of CuSO₄ crystals into water and the colour of water changes. 

6. From the above observations, we found that the particles of solids diffuse into liquids.