Humidity

particles from their solution cannot be separated by centrifugation

HCl

similar mass number

protein synthesis

parenchyma cells

five kingdoms

0.83 \(ms^{ -2 }\)

torque

A campsite in Antarctica

Pushed over smooth rollers

2L

Symptoms of a disease

pulse

Xanthium, Parthenium, Cyperinus

1. Solids have melting and boiling points above room temperature.
2. Liquids have melting points below room temperature and boiling point above room temperature.
3. Gases have melting and boiling points below room temperature.

(a) The amount of sugar will be more because sugar is more soluble in water than salt at a given temperature.
(b) When we cool, the contents of two beakers, salt will be precipitated out first.

The chemical formula of a compound is the symbolic representation of its composition.It gives the number and kinds of atoms which are chemically united in a given compound.For example, the chemical formula of hydrogen sulphide is HS.It tells that in hydrogen sulphide two hydrogen atoms and one sulphur atom are chemically united.

Chadwick discovered neutrons.Hydrogen atom contains one proton and helium atom contains 2 protons.Therefore, it was thought the relative atomic mass of helium atom should be two.But the relative atomic mass of helium is 4.On examination of nuclei of atoms, it was discovered that nuclei of atoms contain another particle of the same mass as protons but of neutral charge.These were called neutrons.

(i) To avoid infection, SavlonlDettol is disinfectant.
(ii) I can use Band-aid.
(iii) (a) The teacher conveyed the importance of First Aid.
(b) Demonstrated how the students can manage such small cuts.

Characteristic is a particular from or a particular function. For example, generally human being has five finger in each hand. Thus, presence of five finger in each hand is a characteristic. Similarly, animals can run but trees like banyan tree cannot run, is also a characteristic.

Suppose we talk for half an hour to reach school from our house Then,
Time taken = 0.5 h
Average speed = 4km \(h^{ -1 }\)
Distance of the school from our house = Average speed x Time taken
= 4km \(h^{ -1 }\) x 0.5 h=2 km.

As the man jumps out from a moving bus, his feet suddenly come to rest on touching the ground while the upper part of his body continues to move forward. That is why he falls with his forward. In order to save himself, he should run through some distance in the forward direction. 

Ball B will undergo maximum apparent loss in weight because it displaces maximum volume of liquid.

W = 48.4J, s = 40 cm = 0,40 m
Force F = W/s = 48.4J/0.40 = 121 N

The persistence of sound in a big hall or auditorium due to the repeated reflections of sound is called reverberation.
(i) By covering the walls and roof of the halls with sound-absorbing materials.
(ii) By providing heavy curtains with folds.

(i) Many municipal corporations are trying water harvesting mainly to maintain the underground fresh water reservoirs of fresh water. We obtain underground fresh water through wells or tube-wells.
(ii) Due to combustion of fossil fuels, air is polluted from oxides of nitrogen \(\left( { NO }_{ 2 } \right) \) and sulphur \(\left( { SO }_{ 2 } \right). \) These oxides when dissolve in rainwater form respective acids. So, when air is polluted by oxides of nitrogen and sulphur the rainwater contains traces of acids.

Macro-nutrients: Nutrients which are utilized by plants relatively in large quantities are called macro-nutrients.
For example: Nitrogen, Phosphorus.
Micro-nutrients: Nutrients which are utilized by plants relatively in small quantities are called micro-nutrients.
For example: Zinc, Copper.

Water exists as solid water (ice), liquid water (water) and gaseous water (steam).The melting point of ice is 0⁰C.It does not mean that water is not available as solid at 0⁰C.It only means that at this temperature ice starts melting and at 0⁰ C both ice and water are in equilibrium.Similarly the boiling point of water as 100⁰ C does not mean that at this temperature there is no liquid water present.At 100⁰C actually both water and steam are in equilibrium.At these temperatures with a little change in energy one can move to either of the stats.This energy is called latent heat.The word 'latent' is used to signify that this heat is taken up or given by the system but not shown by rise or fall in temperature.

Air is a homogeneous mixture of several gases. It can be established as follows:
(i) The amounts of gases present in air at different places varies only marginally.
(ii) No definite formula can be assigned to air.
(iii) The different gases present in air are separable by a physical process: fractional distillation of liquid air.
(iv) The properties of air are the properties of its constituents. Air supports combustion because of oxygen present in it. Air turns lime water milky due to the presence of carbon dioxide in it.

Amount of actinium left after 15 seconds \(={1\over2}\times0.1=.05g\)
Amount of Actinium left after another 15 seconds (i.e., 30 seconds) \(={1\over2}\times.05=.025g\)
Amount of Actinium left after another 15seconds (i.e., 45 seconds)\(={1\over2}\times0.25=.0125g\)
Amount of Actinium left after another 15 seconds (i.e., 60 seconds=1 min.)\(={1\over2}\times.0125\)
=.00625 g=6.25mg.

(i) Extracellular digestion. Sometimes lysosome enzymes are released outside the cell to break down extracellular material.
(ii) Digestion of foreign material. lysosomes also destroy and foreign material which enters inside the cell such as bacteria.
(iii) Cellular digestion. In damaged cells, ageing cells or dead cells lysosomes get ruptured, and enzymes are released. These enzymes digest their own cell.
Lysosomes contain about 40 hydrolytic enzymes. When the cell gets damaged, lysosomes burst and their enzymes digest their own cell. So, lysosomes are called 'suicide bags'.
Foreign materials entering the cell, such as bacteria or food, as well as old organelles end up in the lysosomes, which break them up into small pieces.

The differences between tendon and ligament are as follows:

(a) Speed is defined as the distance travelled by a body per unit time.
(b) The SI unit of speed is m s^-1
(c) Average speed is the total distance travelled by a body, divided by the total time taken to cover that distance.
(d) No, the average speed of an object can't be negative.

Here     m = 1,200 kg
Initial velocity,  \(v = 90 \ km/h = 90 \times \frac {5}{18} \ m \ s^{-1}=25 \ m s ^{-1}\)
Final velocity,    \(u = 18 km/h = 18 \times \frac {5}{18} = 5m\quad s^{-1}\)
Time,    t  =  4 s
Accleration,   \(a = \frac {v-u}{t}=\frac {5-25}{4}=-5 m \ s^{-2}\)
magnitude of accleration  \(= 5 m \ s^{-2}.\)
Change in momentum \(= m \left( v- u \right)=1,200 \left(5-25\right)\)
 \(= - 24,000 \ kq \ m \ s^{-1}.\)
Magnitude of change in momentum \(= 24,000 \ kq \ m \ s^{-1}.\)
Magnitude of force \(= \frac {Change \ in \ momentum}{time \ taken}=\frac {24,000}{4}=6,000 \ N.\)

Given, H = 1000 m, v = 0, g = 9.8 m/s²
(i) From the third equation of motion,
v² = u² +2gH
\(\Rightarrow\) 0 = u² - 2 x 9.8 x 1000
u = \(\sqrt { 2\times 9.8\times 1000 } \)
= \(\sqrt { 19600 } \) =140 m/s
(ii) From the first equation of motion,
v = u+ gt
\(\Rightarrow\)0=140-9.8t
\(\Rightarrow\) \(t=\cfrac { 140 }{ 9.8 } =14.28s\) 

(i) Yes, Suma is doing work by pushing water in the backward direction.
(ii) No, because the force exerted by donkey in the upward direction is perpendicular to the horizontal displacement of the load.
(iii) Yes, work is done in lifting water against the force of gravity.
(iv) No, because the leaves of plants remain at rest during photosynthesis.
(v) Yes, engine is doing work in pulling the train.Both the applied force and displacement are in same direction.
(vi) No, because food grains reamins at rest.
(vii) Yes, work is done by the wind in moving the sailboat.

1. Filling of bitches with mud where mosquitoes breed
2. Water tanks should not be left open.Water in the coolers should be changed frequently.
3. Water surfaces are sprayed with kerosine oil,petroleum,paraffin,oil,etc.so that mosquitoes are killed in their larval or pupal stages.
4. By fumigating kill the adult mosquitoes ,effective in driving the mosquitoes out.
5. Spraying D.D.T ,b.H.C lindane and other effective insecticides to kill the mosquitoes (chemical control)
6. By the use of mosquito nets and use of mosquito repellents.
(b) Community service and social responsibility.

The concentration of carbon dioxide in the atmosphere is increasing due to the current global trend of deforestation and increasing combustion of fossil fuels. A part of the sunlight incident on the earth reflected back in the form of infrared radiations. This infrared radiation are absorbed by the carbon dioxide molecules. hence, the envelope of CO₂  of the atmospheric air would be able to trap larger proportion of the infrared radiations if the concentration of CO₂ is increased, thereby heating the atmosphere.
This heating of the absorption of infrared earth's temperature and may cause melting of glacier and thereby flooding the coastal plains.
Greenhouse gases:
(i) CO ₂ ,  
(ii) Methane (CH₄ ) and
(iii) Nitrogen oxide.

Objectives of mixed cropping are to
(i) minimize risk and
(i) give insurance against failure of one of the crops.
Criteria for selection of the crops for mixed cropping are:
(i) Duration of Crops: Two crops growing together should have different durations for maturity. One should be of long duration and other should be of short duration.
(ii) Growth Habit: One crop should be tall growing and the other be short growing.
(iii) Root Pattern: One should be deep rooted where as other should be shallow rooted.
(iv) Water Need: One component crop should need lesser water than the other.
(v) Nutrient Demand: Component crops should have different nutrient requirements.

(a) Naphthalene has the property of sublimation.So even at room temperature, it evaporates to vapours.
(b) the molecules of gas are continuously moving at random either striking among themselves or with the walls of the container.The pressure on the walls of container is the force per unit area with which the moving gas particles strike per unit area of the containing vessel.

Comparison of properties of true solution, colloidal solution, and suspension

Test of a colloidal solution or a suspension.
(i) A colloidal solution is turbid and particle settles down on adding a salt. In a suspension, particles settle down on keeping under the influences of gravity.
(ii) If the particles in a heterogeneous and opaque solution can be seen with naked eyes and get settl on keeping, then it is a suspension.

From table
Number of proton oxygen atom=8
Number of neutron oxygen atom=8
Mass number of oxygen = 8+8=16U
Number of protons in sulphur atom=16
Number of neutrons in sulphur atom=16
Mass number of sulphur atom=16+16=32U

(i) We will give ORS (Oral Rehydration Solution) from time to time till we reach to doctor or doctor comes to attend the patient. ORS is available in powder form packed in sachets.
(ii) We can make ORS in home by the following way:
Ingredients
1. One level teaspoon of salt
2. Eight level teaspoon of sugar
3. One litre of clean drinking or boiled water and then cooled (5 cupfuls-each cup about 200 .ml.),
Preparation Method
Stir the mixture till the salt and sugar dissolve.
(a) Arrange community lectures, debates to sensitise harmful effects of dehydration of the body.
(b) Conveying importation of ORS and its preparation in home

Plants and Animals differ as given in the table below:

Graphical representation of motion. The nature of motion of bodies can be easily studied from its graphical representation here ,time is plotted along X-axis while distance or velocity is plotted along y-axis Graphs give detailed information about the nature of motion than when motion is expected in a tabular form.
Uses of graphs
(i) From distance -time graph the postion of the body at any instant of time can be determined
(ii) Distance covered by the body during particular interval of time can be seen from the graph.
(iii) By simply looking at the graph one can tell wheteher motion is uniform or not
(iii) The velocity of the body at any instant of time can be determined
(iv) By simply looking at the graph ,one can tell whether motion is uniform or not
(v) Slope of velocity -time graph gives the acceleration of the body
(vi) Graphs are very useful for comparing the motions of two moving bodies Distance time graphs easily tell when and where one body crosses 

Newton's first law of motion. According to this law, a body at rest or in uniform motion will remain at rest or in uniform motion unless an unbalanced force acts upon it. This law consists of three parts:
(i) First part, says that a body at rest continues in its state of rest. For example, a person standing in a bus falls backward when the bus suddenly starts moving forward. When the bus moves, the lower part of his body begins to move along with the bus while the upper part of his body continues to remain at rest due to inertia. That is why a person falls backward when the bus starts.
(ii) Second part, says that a body uniform motion continues moving in straight line path will a uniform speed. for example, when a moving bus suddenly stops, a person sittng in it falls forward. As the bus stops, the lower part of his body comes to rest along with the bus while upper part of his body continues to remain in motion due to inertia and so he fall forward.
(iii) Third part, says that a body moving with a uniform speed in a straight line cannot change itself its direction of motion. For example, when a bus takes a sharp turn, a person sitting in the bus gets a force acting away from the center of the curved path due to his tendency to move in the original direction. He has to hold on a support to prevent himself from swaying away in the turning bus.

(i) \(u=0,\quad g=-9.8\quad m/s^{ 2 },\quad s=-4.9m\) 
\(s=ut+\frac { 1 }{ 2 } { gt }^{ 2 }\) 
\(\therefore -4.9=0-\frac { 1 }{ 2 } \times 9.8\times { t }^{ 2 }\quad or\quad t=\sqrt { \frac { 2\times 4.9 }{ 9.8 } } =1\ s.\) 
(ii) \(u=0,\quad s=-4.9m,\quad g=-9.8\quad m/s^{ 2 },\) 
\({ v }^{ 2 }-{ u }^{ 2 }=2gs\) 
\(\therefore \ { v }^{ 2 }-0=2\times (-9.8)\times (-4.9)\quad or\quad v=\sqrt { 2\times 9.8\times 4.9 } =9.8\ m/s.\) 
(iii) \(u=0,\quad g=-9.8\quad m/s^{ 2 },\quad s--7.9m\)
\(\because { v }^{ 2 }-{ u }^{ 2 }=2gs\) 
\(\\ \therefore { \ v }^{ 2 }-0=2\times (-9.8)\times (-7.9)\) 
\(\\ v=\sqrt { 2\times 9.8\times 7.9 } m/s=10.46\quad m/s\)
(iv) Acceleration after 1 s and after 2 s will be 9.8 m/s² , because acceleration due to gravity remains almost same for small heights.

No. The bundle of hay remains stationary i.e., displacement is zero.So, the work done is also zero.

Echo. Echo is the phenomenon of repetition of a sound due to its reflection from the surface of a large obstacle. When a loud sound is produced in an empty hall, the same sound is heard again after some time.
Conditions for the production of an echo:
(i) Sufficient time gap between original and reflected sounds. Due to persistence of hearing, we keep on hearing a sound for 0.1 s, even after reflected sound must reach the ear 0.1 s after the direct original sound.
(ii) Sufficient distance between the source of sound and the obstacle. The speed of sound in air is 344 m/s. The distance traveled by sound in\(0.1\quad s=344\times 0.1\times 0.1=34.4\quad m\) . So echo will be heard if the minimum distance between the source of sound and the obstacle =34.4/2=17.2 m.
(iii) Nature of the obstacle. For the formation of echo, the reflecting surface must be rigid such as a building, hill or cliff.
(iv) Size of the obstacle. Echoes can be heard if the size of the reflecting surface is quite large.

(a) (1) Before selling of old fridge or AC to junk purchaser remove the CPC compressure Take care that its gas does not leak in the atmosphere
(2) While purchasing new air conditioner or refrigeration,keep in mind it is ozone friendly i.e..it should contain HFC (Hydro-fluro carbon) instead of CFC
(3) Many mattresses and pillows are made of chemicals which harm ozone, Beware of them and purchase only ozone friendly products.
(4) While purchasing room refreshers,paint,etc., check that they do not contain CFCs
(b) By organising campaigns on the above said point for protection of ozone layer amongst masses they depict the following values:
(1) Relationship of common man and community with the ozone layer.
(2) Environmental protection.

The various factors responsible for grain loss during storage are:
(i) Biotic factors: Insects, Rodents (mice), Birds, Fungi, Bacteria, Mites, ect.
(ii) Abiotic factors: Inappropriate temperature, moisture, moisture contents of seeds, dampness of storage godown ect.
The above factors cause loss in weight, degradation in quality, discolouration of produce ect.
Measures for safe storage of grains: 
(i) Drying: Grains to be stored ideally should contain below 9% water content/moisture. When grains are harvested, usually contain 15 to 35% moisture. These freshly harvested grains are dried under the sun and then in shade to reduce the moisture content. Commercially grains are dried by mechanical driers with hot air blowing process.
(ii) Maintenance of hygiene: Grains should be kept in godowns that
(a) are very clean and do not have garbage, refuse, webs etc.
(b) do not have cracks, holes in walls, floor and ceilings.
(c) have clean and fresh gunny bags or are well treated with fumigate or dried under sun.
(d) have earthen pots, if to be used for storage, well cleaned and properly exposed to sun before use.
(iii) Prophylactic treatment: Godowns, gunny bags to be used for storage must be properly treated with fungicides, insecticides and other required pesticides by dusting, spraying or fumigation. Insecticides and fungicides should be mixed with grains that .are to be used for seed sowing.
(iv) Use of improved structures: Structures such as Pusa Bin, Pusa Cubicle, Pusa Kothar and Pant Kuthla can be used for storage purpose.
(v) Treatment of the surface area of the store house should be done by spraying mixture of BHC WP (50%), Pyrethrum (2.5 EC) and Malathion (50 EC) for controlling pests.
(vi) Fumigation of the store houses by chemicals such as aluminium phosphide tablets should be done.

(i) Lysosomes are membrane-bound sacs filled with digestive enzymes.These enzymes are made by rough endoplasmic reticulum.
(ii) Lysosomes are a kind of waste disposal system of the cell.
(iii) During the disturbance in cellular metabolism, e.g. when a cell gets damaged, lysosomes present in the cell may burst and the enzymes digest the damaged cell. Hence, lysosomes are called as 'suicidal bags' of a cell.
(iv) Lysosomes break up the foreign materials entering into the cell, such as bacteria or food into smal piece

(i) (a) g on the moon is given by
\({ g }^{ ' }=\cfrac { g }{ 6 } =\cfrac { 9.8 }{ 6 } \)
= 1.63 m/s²
(b) Mass of the person on the moon
=\(\cfrac { 110.84 }{ 1.63 } =68kg\)
(c) Weight of person on the earth = mg
= 68 x9.8
= 666.4 N- m²/kg²
(ii) Weight of a person on the earth will be
\(w=\cfrac { GMm }{ { R }^{ 2 } } \)
where, M = mass of the earth
R = radius of the earth
m = mass of person
and G =6.67 X 10 ^-11 N-m²/kg²