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Ask questions which are clear, concise and easy to understand.

How to solve jee mains physics and maths problems

Posted by Ashok Kumar S (Jul 23, 2017 7:52 p.m.) (Question ID: 6880)

• go through NCERT books of CLass 11 and 12 completely

Answered by Just Henry (Jul 24, 2017 12:17 a.m.)
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17.4 % of K2SO4 at 27°C isotonic with 4% NaOH at the same temperature. If NaOH is 100% ionised than,what is the degree of dissociation of K2SO4. ??

Helppp plzzz!!!!

Posted by Yash Sahu (Jul 23, 2017 9:07 a.m.) (Question ID: 6860)

Which kingdoms among the living organism contains micro organism of chapter microbes in human welfare

Posted by Santosh Chauhan (Jul 23, 2017 9:04 a.m.) (Question ID: 6859)

• Monera,protista and fungi has microscopic organisms in their kingdom.

Answered by Dr. S.K. Raj (Jul 23, 2017 12:12 p.m.)
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When should I use the RHL , LHL and f(x) to define the continuity of a function and when to use f(x) and equate it to its limit?

Posted by Harshit Srivastava (Jul 22, 2017 9:22 p.m.) (Question ID: 6848)

My question is - i am not easily learn derivations of physics ... So what  i do ..

Posted by Aditya Nagar (Jul 22, 2017 8:36 p.m.) (Question ID: 6847)

• Try to understand the concept and physical meaning of the derivative part. Try to solve it in your way of understanding.

Posted by Mukesh Chawda (Jul 23, 2017 6:49 p.m.)
• Solve derivations  by your method in step by step.

Answered by Kriti Bhawsar (Jul 23, 2017 11:10 a.m.)
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chapter 5 and  6 notes in all topics

Posted by Deepak Jha (Jul 22, 2017 8:26 p.m.) (Question ID: 6844)

• You can get it on mycbseguide.com website

Answered by Ashutosh Kumar (Jul 23, 2017 5:54 a.m.)
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sample paper solved

Posted by Deepak Jha (Jul 22, 2017 8:24 p.m.) (Question ID: 6843)

• which sample paper

name it

Answered by Swami Jee (Jul 23, 2017 8:38 p.m.)
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17.4 % of K2SO4 at 27°C is isotonic with 4% NaOH at the same temperature. If NaOH is 100% ionised than what is the degree of dissociation of K2SO4

Posted by Yash Sahu (Jul 22, 2017 7:30 p.m.) (Question ID: 6837)

• Comeonn someone plz help me...

This is really very important!!!!

Posted by Yash Sahu (Jul 22, 2017 8:05 p.m.)

When there is need of calculating goodwill

Posted by Asma Sheikh (Jul 22, 2017 5:38 p.m.) (Question ID: 6836)

• Goodwill is calculated at the time of reconstitution of partnership. It is also calculated at the time of sale of a business enterprise to another business/individual, i.e., when the ownership of the firm/company changes.

Answered by Poornika Aggarwal (Jul 22, 2017 6:38 p.m.)
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When there is need of  calculating goodwill

Posted by Asma Sheikh (Jul 22, 2017 5:37 p.m.) (Question ID: 6835)

• The valuation of the Goodwill of a sole proprietorship is done when the business is being sold, but in case of a partnership firm and a joint stock company goodwill can be sold to some another business entity without selling the whole business. Hence when you are going to sell the goodwill of your business, you should be assured of the value of your goodwill at that particular time.

In case of a Partnership firm, there is a need for the valuation of Goodwill of the Firm in the following cases:

• In the case of a change in the profit sharing ratio of the firm
• In case of admission of a new partner;
• Incase of retirement or death of an old partner;
• In case of Sale / amalgamation of the firm.

In case of a Joint Stock Company, Goodwill is valued in the following circumstances:

• In case of amalgamation of two or more companies;
• In case of taking over of business of a company by another company;
• In case of taking over the business of the company by Government;
• Incase of conversion of shares of one class into another;
• If a company wants to acquire conrol of another company;

Answered by Payal Singh (Jul 22, 2017 6:56 p.m.)
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Answered by Asma Sheikh (Jul 22, 2017 5:46 p.m.)
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What is zen therapy?

Posted by Vridhi Sharma (Jul 22, 2017 12:12 p.m.) (Question ID: 6828)

• A type of therapy that encourages self-understanding through prolonged meditation. It is believed by some to be ineffective, and possibly harmful to those who have a history of psychological vulnerability, alienation, emotional lability and mental disorders.

Answered by Sahdev Sharma (Jul 22, 2017 12:19 p.m.)
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Give the mechanisum of the reaction between propene and HBr in the presence of preoxide

Posted by Jemini Maheshwari (Jul 22, 2017 11:19 a.m.) (Question ID: 6827)

• This rxn.is also called anti markovnikov's law.

Posted by Yash Sahu (Jul 22, 2017 8:20 p.m.)
• Mechanism:-- As in the presence of any peroxide ,the negative part of the alkyl halide( here-Br) always gets attached to that carbon atom of alkene which has more no.of H atom therefore,

CH3CH=CH+ HBr (In peroxide)

----------> CH3CH2CH2Br

Answered by Yash Sahu (Jul 22, 2017 8:19 p.m.)
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dy/dx=x(2logx+1)/siny+ycosy

Posted by Meenakshi Rajput (Jul 22, 2017 5:11 a.m.) (Question ID: 6824)

• {tex}{dy\over dx}={x(2log\ x+1)\over sin\ y+y.cos\ y}{/tex}

{tex} (sin \ y+y.cos\ y)dy = [x(2log\ x+1)]dx{/tex}

Integrating both sides, we get

{tex} \int sin\ y\ dy +\int y.cos\ y\ dy = \int 2x.log\ x \ dx+ \int xdx{/tex}

{tex}-cox \ y + y\ sin\ y + cos \ y = x^2log\ x -{x^2\over 2}+ {x^2\over 2}+C{/tex}

{tex}=> y sin\ y =x^2.log \ x+ C{/tex}

Answered by Sahdev Sharma (Jul 22, 2017 12:18 p.m.)
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Draw a plot showing variation of power of lens with wavelength of incident light

Posted by Jashan Preet (Jul 21, 2017 8:55 p.m.) (Question ID: 6821)

Tan(xo+45o)

Posted by Ashok Kumar S (Jul 21, 2017 7:03 a.m.) (Question ID: 6808)

• Using tan (a+b) = {tex}tan \ a +tan \ b\over 1- tan\ a.tan\ b{/tex}

we get

{tex}tan (x+45) = { tan x + tan 45\over 1-tanx\times tan 45}{/tex}

{tex}{tan\ x + 1 \over 1-tan\ x}\\ [ as \ tan \ 45 = 1]{/tex}

{tex}1+tan \ x\over 1- tan \ x{/tex}

Answered by Sahdev Sharma (Jul 21, 2017 7:32 a.m.)
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All advertising is a social waste. Comment

Posted by Priya Mittal (Jul 20, 2017 5:58 p.m.) (Question ID: 6792)

• Advertising leads to higher prices: Many hold the view that advertising leads to higher prices of goods. Advertising involves considerable expenditure. If that, expenditure is avoided, the cost of goods may be reduced and the consumer can get the product at a cheaper price. If the money spent on advertising is used for improving the quality of the product, consumers may get a better product for the same price.
• Advertising leads to monopoly: It is well known that large business firms establish brand image through advertising. Consumers develop brand loyalty. Then it becomes difficult for new producers to enter the market. In other words, advertising enables the existing large producers to block new competitors from entering the market. Thus, advertising acts as a barrier to entry and thereby leads to monopoly. Moreover, increased advertising often results in increased sales. Due to this possibility, established firms spend more and more on advertising and increase their sales. In this process they earn larger profits which enable them to spend even more on advertising. Thus, new entrants who do not have large financial resources find it difficult to compete with such established firms.
• Advertising results in inefficient resource allocation: Advertisements are intended not so much for the benefit of consumers. They are mainly directed to influence the consumer demand to fit whatever has been produced. In other words, advertisements are aimed mainly to change the tastes of people so that they will buy whatever is manufactured. This leads to distortion in consumption expenditure and increases the producers’ market power. Thus, advertising indirectly determines what people should consume. In this process productive resources i.e., land, labour and capital, may not be used in the best interest of the society.
• Advertising causes undesirable social effects: There are certain other criticisms about the social effects and cultural impact of advertising.

(a) Objectionable appeals like sex, horror, etc., are used in advertisements to attract the customers’ attention.

(b) Consumers are exposed to hundreds and thousands of product appeals which they may not be able to buy and enjoy. This may create frustration and disappointment in many cases.

(c) Advertising is used for promoting objectionable and harmful goods like cigarettes, liquors, etc.

(d) It influences the values and life styles of people in society. Often it is used to promote products that satisfy the materialistic requirements of consumers Advertising is, thus, accused of promoting materialistic values in the society.

(e) Advertisements occasionally portray certain things objectionable to some sections of the society creating tensions between different groups of people.

Answered by Payal Singh (Jul 20, 2017 6:43 p.m.)
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Unpolarized light is incident on a plane surface of glass of refractive index at angle 'i'. If the reflected light gets totally polarized, write the relation between the angle 'i' and refractive index.

Posted by Bini Raju (Jul 20, 2017 9:27 a.m.) (Question ID: 6787)

1.defination of function?

Posted by Rohit Sharma (Jul 20, 2017 4:52 a.m.) (Question ID: 6785)

• A function is a special relation between a set of inputs and a set of permissible outputs with the property that each input is related to exactly one output.

Answered by Sahdev Sharma (Jul 20, 2017 8:40 a.m.)
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Vashvikaran ke daur mai Sanskritic vaibhinnikaran bada hai ya sanskitic samrupta?

Posted by Dheeraj Nautiyal (Jul 19, 2017 10:49 p.m.) (Question ID: 6781)

Posted by Saurav Yadav (Jul 19, 2017 10:20 p.m.) (Question ID: 6778)

• Adsorption is the adhesion of atoms, ions, or molecules from a gas, liquid, or dissolved solid to a surface. This process creates a film of the adsorbate on the surface of the adsorbent.

Answered by Ashutosh Kumar (Jul 20, 2017 10:09 a.m.)
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Q-1 State Huygen's principle of diffraction of light.

Q-2 Unpolarized light of intensity 'I' is passed through a polaroid. What is the intensity of the light transmitted through the polaroid ?

Posted by Bini Raju (Jul 19, 2017 9:16 p.m.) (Question ID: 6775)

• The Huygens-Fresnel principle states that every point on a wavefront is a source of wavelets. These wavelets spread out in the forward direction, at the same speed as the source wave. The new wavefront is a line tangent to all of the wavelets.

Answered by Ashutosh Kumar (Jul 20, 2017 10:11 a.m.)
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What are differences between vitamin and halogen ?

Posted by Ekta Sangwan (Jul 19, 2017 6:04 p.m.) (Question ID: 6764)

• The question seems to be erroneous as  there can not  be any comparision between  vitamins  and  halogen.

Actually the question should be ,

" What aredifferences between vitamins  and  halogen containing  drugs (organic compounds )" ?

Posted by Dr. Kamlapati Bhatt (Jul 20, 2017 10:23 p.m.)
• The question seems to be erroneous  , as  the terms ' vitamin ' and ' halogen  '   are  widely  different  and hence, not  comparable.

Actually ,   the question should be,

" What is the difference between  vitamin  and  halogen containing drugs ( organic  compounds ) " ?

Posted by Dr. Kamlapati Bhatt (Jul 20, 2017 9:34 p.m.)
• Following  are the points  of  differences  between  vitamins   and  halogen containing  drugs ,

 Vitamins are certain organic compounds required in small amounts in our diet but thier defficiency causes deseases.                             Most of the vitamins cannot be synthesised in our body but plants  can synthesise all of them. Different vitamins belong to various chemical classes  and it is difficult to classify them on the basis of their structures. These have been classified  as  (i) fat soluble vitamins  viz. vitamins A,D,  Eand K (ii) Water soluble vitamins , viz. B group vitamins and vitamin C  They perfom  specific biological functions for normal maintenance of optimal growth  and health of organism. Halogen containing drugs These are clinically useful. A few examples are :                                                          Chlorine containing  antibiotic ,                                                                    chloramphenicol is very effective for                                                             treatment of  typhoid                                                                                      fever,chloroquine is used for                                                                       treatment of malaria,Halothane is                                                                  used for as an anaesthetic during                                                               surgery.a hormone thyroxine  is                                                                    produced by iodine in our body .

Answered by Dr. Kamlapati Bhatt (Jul 20, 2017 10:18 p.m.)
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"Brain drain is not good for our nation" write a debate on it.

Posted by Kirti Jain (Jul 19, 2017 4:15 p.m.) (Question ID: 6756)

What is trace matrix?

Posted by Ashok Kumar S (Jul 19, 2017 3:38 p.m.) (Question ID: 6755)

• Sum of diagonal in a matrix is called trace of a matrix

Answered by Arun Kumar (Jul 22, 2017 2:12 p.m.)
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State culomb's law in vector form .

Posted by Prashant Kumar (Jul 19, 2017 9:15 a.m.) (Question ID: 6754)

Slow reactions requires low activation energy as compared to fast reactions. Do you agree with this statement?

Posted by Mamta Vaish (Jul 19, 2017 12:47 a.m.) (Question ID: 6752)

• No

Posted by Nitin Mhamane (Jul 19, 2017 10:37 a.m.)
• No because the threshold energy remains the same irrespective of it's speed. Hence speed do not depends upon the activation energy

Answered by Durgesh Bishi (Jul 19, 2017 2:53 p.m.)
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• No because the threshold energy remains the same irrespective of it's speed.. Hence speed do not depends upon the activation energy

Answered by Durgesh Bishi (Jul 19, 2017 2:53 p.m.)
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What is the value of rate constant K at extremely high temperature (T =infinity). Is this rate constant possible?

Posted by Mamta Vaish (Jul 19, 2017 12:46 a.m.) (Question ID: 6751)

• Rate constant k=AeEa/RT

AS temperature is infinite, K=A.

Answered by Durgesh Bishi (Jul 19, 2017 2:56 p.m.)
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• At 338K the value i <font size="+1">2.40 x 10-3</font>

Answered by Dr Pathikrt Banerjee (Jul 19, 2017 1:03 p.m.)
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Can a reaction have negative activation energy?

Posted by Mamta Vaish (Jul 19, 2017 12:44 a.m.) (Question ID: 6750)

• Yes sometime it is negative in case of backward reaction

Answered by Durgesh Bishi (Jul 19, 2017 2:57 p.m.)
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• Reaction never have negative activation energy.Its always a positive quantity.

Answered by Nitin Mhamane (Jul 19, 2017 10:38 a.m.)
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two cells of e.m.f E1 and E2 (E1>E2) are connected as shown in the figure. when a potentiometer is connected between A and B , the balancing length of the potentiometer wire is 300 cm. on connecting the same potentiometer between A and C, the balancing length is 100 cm , calculate the ratio of E1 and E2

Posted by Sushil Arora (Jul 18, 2017 10:21 p.m.) (Question ID: 6745)

What effect does doubling the initial concentration of a reaction on the half life of a zero order reaction.

Posted by Mamta Vaish (Jul 18, 2017 10:02 p.m.) (Question ID: 6744)

• There is no effect of altering the concentrations of reactant on zero order reaction,since they are concentration independent.

Answered by Nitin Mhamane (Jul 19, 2017 10:40 a.m.)
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