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कुण्डली में उत्पन्न वैद्युत वाहक बल e = NBAω sinωt

sinωt की महत्तम मान 1 होता है तब वैद्युत वाहक बल e = NBAω

different colours are separated.

Chromatography

Option : (d) nuclear reactions

• Elements from atomic number 104 to 118 are called postactinoid elements. 
• The post actinoid elements known so far are transition metals. 
• They can be synthesised in the nuclear reactions. 
• As they have very short half life period, it is difficult to study their chemistry. 
• Ruiherfordium forms a chloride (RfCl₄) similar to zirconium and hafnium in + 4 oxidation state. 
• Dubniurn resembles niobium and protactinium. 

14 elements after actinium is called Actinides.

Cooker is made of metal. 

When food is cooked in it, it gets heated and the whole of its body becomes hot due to thermal conductivity. 

Hence with the plastic handle we can easily lift the hot cooker as plastic is a bad conductor of heat.

Plastic or wood are bad conductors of heat and electricity. 

Electric boards are made up of plastic or wood. 

So that while touching we will not get electric shock.

1. Camphor is a sublimate substance. 

2. When a box of camphor is opened it changes its state from solid to gas or vapour state. 

3. This change takes due to the process of sublimation where camphor absorbs heat from surrounding to change from solid to gaseous state. 

4. Camphor particles in gaseous state start spreading all around.

5. Hence on opening a box of camphor its smell spreads all around.

(a) Nails are made of plastic :

If nails are made of plastic, they will not be able to pierce through other substances on being pushed or forced by a hammer. 

Plastic lacks the property of hardness.

(b) A bell is made of wood :

1. If a bell is made of wood it will never make a ringing sound. 

A wooden bell does not have the property of being sonorous. 

2. Sonority is the property of metals to produce a ringing sound.

(c) Rubber is not fitted on a pair of tongs :

1. Rubber is a bad conductor of heat and electricity. It will not allow heat to pass to the hands/handle of the tongs, thus protecting us.

2. Pair of tongs are made up of metals which conduct heat and electricity. They have file property of thermal conduction and electrical conduction.

3. If rubber is not fitted on a pair of tongs, we will not be able to lift hot objects with it.

(d) A knife is made of wood :

Wood does not have the property of malleability. 

Therefore,

The edge of wooden knife will be blunt. 

Hence,

We will not be able to cut anything with it.

(e) An axe is made of rubber :

1. If an axe is made of rubber, it will not be used to cut wood or tree. 

2. Rubber does not have the property of hardness that is required to push through to cut it.

(a) Tollen's reagent test: Add ammoniacal solution of silver nitrate(Tollen's Reagent) in both the solutions. Butanal gives silver mirror whereas Butan-2-one does not.

(b) Add neutral FeCl3 in both the solution, phenol forms violet colour but benzoic acid does not

Phenol gives a violet colouration with FeCl₃ solution while methanol does not.

(i) C₆H₅OH + NaHCO₃  No effervescence

C₆H₅COOH + NaHCO₃ → C₆H₅COONa + H₂O + CO₂ (effervescence )

(ii) CH₃-CH₂ –CH₂OH → No Turbidity

CH₃-CHOH–CH₃ → Turbidity produced with in five minutes 

(a) The elements are classified into groups so that the elements with similar properties fall in the same group and hence the study of a large number of elements is reduced to the study of a few group of elements.

(b)(i) Increasing atomic masses

(ii) Grouping together of elements having similar properties.

(c) In order to make sure that the elements having similar properties fell in the same vertical column or group, Mendeleev left some gaps in his periodic table.

(d) Out of eight groups in the original periodic table of Mendeleev, first seven groups are of normal elements and eighth group is of transition elements. Noble gases were not known at that time. So, there was no group of noble gases in Mendeleev’s table.

(e) The isotopes of chlorine, Cl-35 and Cl-37 are placed in the same slot because they have similar chemical properties and same atomic number.

Combing : The pulling of fleece through the metal teeth of a combing machine is called combing.

A= CH₃CH₂CN , B= CH₃CH₂CHO, C= CH₃CH₂CH₃

A=(CH₃-CH₂-CN),B=(CH₃-CH₂-CHO),C=(CH₃-CH₃)

Detergents, shampoos, medicines, various food flavours, food colours, etc. are different types of chemicals that we come across in everyday life.

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Chemistry is that the study of matter experiencing transition, chemistry, in fact, goes beyond its conventional meanings. Chemistry has had a detailed link with the everyday actions of folks since the evolution of mankind itself. Each matter is chemistry-related even we humans are made from chemicals. Chemistry plays an important role in characterizing this industrial world. Chemistry may be a huge part of our everyday lives. 

This can be successively present in every part of our lives. within the food we consume, the air we drink, the washing of chemicals, our feelings, and practically any surface we will see or touch, we discover chemistry in everyday life.

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(b) Liquid X is sodium carbonate and the gas Y is CO₂

V_rms = √50/3V = 4.08V

No. of moles in 32g of O₂ = 1

No. of moles in 16g of O₂ = 1/9 x 16 =1/2

As pv = nRT and n=1/2

So, PV=1/2 RT

Specific heat of a gas at constant volume is equal to f/2R.

For monoatomic gases f = 3 so C_v = 3/2 R.

For diatomic gases f = 5 so C_v = 5/2 R.

Hence the specific heat for monoatomic gas is less than that for a diatomic gas.

(a) Diamond is the hardest known naturally occurring non-metalic substance.

(b) Graphite, an allotrope of carbon is a non-metal which is a good conductor of heat and electricity.

Lustre means the shine which is possessed generally by all the metals. Nonmetals generally do not possess any kind of lustre. 

Example of non-metals which possess lustre are carbon as diamond and iodine.

Gold and Platinum belong to class of noble metals in the sense that gold and platinum do not react with almost any chemical reagent. 

Aqua Regia is the chemical mixture which consists of 3 parts of concentrated hydrochloric acid and 1 part of concentrated nitric acid and this mixture can dissolve gold and platinum. 

The reaction is as follows: 

Au + HNO₃ + 4 HCl → HAuCl₄ + NO + 2 H₂O

Less reactive metals do not displace hydrogen from the acids. Reactive metals like sodium, magnesium etc displace hydrogen from acids to form respective chlorides.

Reaction: 

2Na + 2HCl → 2NaCl + H₂ 

Mg + 2HCl → MgCl₂ + H₂

Salt

X is like sodium carbonate, Na₂CO₃ , which is made from a strong base and a weak acid. On dissolving in water, salt X gets hydrolysed to form some strong base and some weak acid. The strong base thus formed makes the solution alkaline which turns red litmus blue.

(i) Number of moles = \(\frac{7.85}{56}\) = 0.1401 mol

(ii) 7.9 mg = 0.0079 g

Number of moles of Ca = \(\frac{0.0079}{40}\)

= 0.000198 mol

When two elements combine with each other to form more than one compound, the weights of one element that combine with a fixed weight of the other are in a ratio of small whole number.

For example: There are five distinct oxides of nitrogen and the weight of oxygen in combination with 14 grams of nitrogen are in increasing order 8, 16, 24, 32 and 40 grams or in ratio of 1, 2, 3, 4, 5.

SI System is an International System of units.

Some derived quantities are speed, velocity, area, volume, density, acceleration, force, pressure, etc.

The quantities that are obtained by combining fundamental quantities either by multiplication or division or both operations are called derived quantities.

Here Quantity on y - axis / Quantity on x - axis  

= Displacement (m) / Time (s) = Velocity (m/s)

The ratio explains the physical quantities on the y – axis and x – axis is velocity.

It is depending upon conditions of the experiment.

Slope of the x – axis is zero.

Two effects caused by refraction of light are:

– a pool of water appears to be less deep than it actually is.

– an object placed under water appears to be raised.

This is due to refraction of light.

Due to refraction of light, it is difficult to shoot a fish swimming in water. 

Reason : 

The light rays coming from the fish towards shooter, bend at water-air interface. So, shooter sees only image of the fish, but not actual fish.

Good conductors:

The substances which conduct heat easily are called good conductors of heat.

All metals are good conductor.

eg: Steel, silver, Aluminium etc.

Insulators:

The substances which do nor conduct heal easily are called insulators or bad condiciors of heal.

eg: Glass. wood, air, paper. etc.

[Note: In general, good conductors of heat are also good conductors of electricity, while bad conductors of hear are had conductors of electricity.]

A hunter wanted to kill the dove.

The dove dropped a leaf into the water.

• tan – ant
• edvo – dove
• waror – arrow
• vrire – river
• afle – leaf
• tehnur – hunter

The ant climbed on the leaf dropped by the dove to save its life.

A dove came for the ant’s help.

The ant climbed the hunter’s foot and bit him. Thus, it saved dove’s life.

The ant went to the river to drink water.

• Vertebrates have a true vertebral column and internal skeleton.
• Skeleton allowing a completely different distribution of muscle attachment points to be used for movement. 
• Vertebrates are bilaterally symmetrical, triploblastic coelomic, and segmented. 
• Vertebrates have complex differentiation of body tissue and organs.

Correct option is D) Dolphin

Correct option is A) Snake

According to the speaker in ‘When You are Old’, the lady will be grey and full of sleep when she sits nodding by the fire.