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A submarine emits a sonar pulse which return from an underwater cliff in 1.2 seconds if the speed of sound in a sea water is 1530 metre per second how far is the Cliff from the submarines

Posted by priyanshu kohli (Mar 23, 2017 7:59 p.m.) (Question ID: 4460)

  • Answers:
  • Time =1.2second

    Distance = ?

    Speed = distance travelled /time taken

    1530=distance/1.2

    Distance = 1530×1.2 = 1836m

    So1836m far cliff from submarine

    Answered by Tanisha Jain (Mar 23, 2017 9:22 p.m.)
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In a factory 4 bulb 100 watt each and 5 fans of 110 what is operate for 12 hours daily. calculate the unit of electricity consumed also find the total expenditure of 1 unit cost rupees 2.50

Posted by priyanshu kohli (Mar 23, 2017 7:54 p.m.) (Question ID: 4459)

  • Answers:
  • Ans. Power of 4 bulbs of 100 Watt = {tex}4\times 100 = 400W = 0.4KW{/tex}

    Power of 5 Fans of 110 Watt = {tex}5\times 110 = 550W = 0.55KW{/tex}

    Total Power = 0.4 + 0.55 = 0.95KW

    Time = 12hours

    Electricity Consumed = {tex}Power \times time{/tex}

    => {tex}0.95\times 12 = 11.40 \space KWh{/tex}

    Rate of Unit = 2.50 Rs.

    Total Expenditure = {tex}11.40 \times 2.50 = 28.50 Rs{/tex}

    Answered by Naveen Sharma (Mar 24, 2017 8:44 a.m.)
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Loaded test tube placed pure milk sinks to a certain mark m and now some water is mixed with the milk will a test tube sink more or less explain

Posted by priyanshu kohli (Mar 23, 2017 7:50 p.m.) (Question ID: 4458)

  • Answers:
  • Loaded Test tube (Lactometer) will sink more as the desnity of milk is decreased due to addition of water.

    Answered by RAJENDRA SINGH (Mar 24, 2017 9:43 a.m.)
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A force of 300 Newton acts on a surface of area 10 centimetres square calculate thrust and pressure calculate the change in pressure is the area increase to 50 centimetre square

Posted by priyanshu kohli (Mar 23, 2017 7:44 p.m.) (Question ID: 4457)

  • Answers:
  • Force = 300N

    Area of square = 10 cm2 = 0.01 m2

    Thrust = Force/ area = 300N/ 0.01 m2 = 30000 Pa.

    New area= 50 cm2 = 0.25 m2

    new pressure = 300/0.25 = 1200 Pa.

    Answered by RAJENDRA SINGH (Mar 24, 2017 9:52 a.m.)
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The mass of a iron cube having an edge length 1.8 centimetre is 70 gram find density

Posted by priyanshu kohli (Mar 23, 2017 7:33 p.m.) (Question ID: 4456)

  • Answers:
  • Ans. Edge of iron cube = 1.8 cm

    Volume of iron cube V = {tex}1.8\times 1.8\times 1.8 = 5.832cm^3{/tex}

    Mass of iron cubd m = 70g 

    {tex}Density \space \rho = {mass \over volume } ={ 70\over 5.832}{/tex}= 12.0027g/cm3

    Answered by Naveen Sharma (Mar 23, 2017 10:30 p.m.)
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How do you determine the maximum number of electron that can be accommodated in particular cell of an atom

Posted by priyanshu kohli (Mar 23, 2017 7:31 p.m.) (Question ID: 4454)

  • Answers:
  • By the formula of (2n²)

    Like for the k shell = we know that k shell is the first shell of atom so by using above formula we easily calculate the maximum number of electon accomondate in a shell where n is the no. of shell 

    (2n²)= 2×(1)²=4

    So k shell have maximum four electrons

    So by using this formula we find no. Of electrons in L shell M shell and so on.....

    Answered by Tanisha Jain (Mar 23, 2017 9:33 p.m.)
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Classify the disease into categories on the basis of period of their appearance and explain in brief. give two example of disease of each category.

Posted by Sahil Jaiswal (Mar 23, 2017 12:21 p.m.) (Question ID: 4440)

  • Answers:
  • Two categaries of disease on the basis of period of their appearance are

    a. Acute disease

    b. Chronic disease.

    Answered by RAJENDRA SINGH (Mar 23, 2017 6:30 p.m.)
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define avogadro constant

Posted by Aashish Dewangan (Mar 23, 2017 8:07 a.m.) (Question ID: 4431)

  • Answers:
  • Avogardo number is the a constant that represpents 6.22 x 1023 particles. it is the number of particles present in one mole of  any element or molecule.

    Answered by RAJENDRA SINGH (Mar 23, 2017 8:28 a.m.)
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What is gravitation

Posted by Lucky Boy (Mar 23, 2017 7:36 a.m.) (Question ID: 4430)

  • Answers:
  • Gravitation is the force by which earth attracts all the objects towards its centre.

    Answered by RAJENDRA SINGH (Mar 23, 2017 8:29 a.m.)
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what are ions?

 

Posted by HARSH SINGH (Mar 22, 2017 9:08 p.m.) (Question ID: 4421)

  • Answers:
  • Charge particles are called ions. Positevely charged ions are called cation and negatively charged ions are called anion.

    Answered by RAJENDRA SINGH (Mar 22, 2017 9:46 p.m.)
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any four characterstics of the frog?

 

Posted by HARSH SINGH (Mar 22, 2017 9:08 p.m.) (Question ID: 4420)

  • Answers:
    • Frog is an amphibian.
    • It is cold blooded animal.
    • It can live in water as well as land.
    • body is soft and slippery.
    Answered by RAJENDRA SINGH (Mar 22, 2017 9:49 p.m.)
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what is atomic no.?

 

Posted by HARSH SINGH (Mar 22, 2017 9:07 p.m.) (Question ID: 4419)

  • Answers:
  • The number of protons present in the nucleus of an atom is called atomic number.

    Answered by RAJENDRA SINGH (Mar 22, 2017 9:50 p.m.)
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what is nomenclature?

 

Posted by HARSH SINGH (Mar 22, 2017 9:07 p.m.) (Question ID: 4418)

  • Answers:
  • The process of naming scientifically following rules is balled nomenclature. In biology it is called as binomial nomenclature.

    Answered by RAJENDRA SINGH (Mar 22, 2017 9:51 p.m.)
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what is the symbol,atomic no. and atomic mass of sodium?

 

Posted by HARSH SINGH (Mar 22, 2017 9:07 p.m.) (Question ID: 4417)

  • Answers:
  •  symbol- Na

    atomic no- 11

    atomic mass- 23

    Answered by anisha grover (Mar 22, 2017 9:30 p.m.)
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what is nucleus of an atom?

 

Posted by HARSH SINGH (Mar 22, 2017 9:06 p.m.) (Question ID: 4416)

  • Answers:
  • The centre of atom where proton and nuetron are present is called as nuclus. Nucleus is positively charged.

    Answered by RAJENDRA SINGH (Mar 22, 2017 9:53 p.m.)
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who found electrons?

 

Posted by HARSH SINGH (Mar 22, 2017 9:05 p.m.) (Question ID: 4415)

  • Answers:
  • Electron is discovered by J J Thomson.

    Answered by RAJENDRA SINGH (Mar 22, 2017 9:54 p.m.)
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what is scientific name of tiger?

 

Posted by HARSH SINGH (Mar 22, 2017 9:05 p.m.) (Question ID: 4414)

  • Answers:
  • Scientific name of tiger is Panthera tigris

    Answered by RAJENDRA SINGH (Mar 22, 2017 9:57 p.m.)
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what is scientific name of humans?

Posted by HARSH SINGH (Mar 22, 2017 9:04 p.m.) (Question ID: 4413)

  • Answers:
  • Homo sapience

    Answered by RAJENDRA SINGH (Mar 22, 2017 10 p.m.)
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what are phanerorams?

 

Posted by HARSH SINGH (Mar 22, 2017 9:04 p.m.) (Question ID: 4412)

  • Answers:
  • Ans. Phanerogams are flowering or seed-bearing plants. They are the most advanced plants. They possess well-developed roots, stems, leaves and flowers.

    Answered by Naveen Sharma (Mar 22, 2017 11:26 p.m.)
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In an experiment to prove the law of conservation of mass in a chemical reaction,the solution of lead nitrate and sodium chloride were mixed together.The colour of precipitate obtained would be-

a)orange

b)red

c)black

d)white

Please sir answer this question with explanation and thanks for previous answers.

Posted by JD Shukla (Mar 22, 2017 8:11 p.m.) (Question ID: 4407)

difference between pteridophyta and brophyta 

Posted by Akshat Shah (Mar 22, 2017 4:02 p.m.) (Question ID: 4393)

  • Plzz tell

     

    Posted by raj kumar chhabra (Mar 22, 2017 4:51 p.m.)
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  • Answers:
  • Bryophytes are plants without vascular system without well-differenciated stem, root and leaves.

    Pteritophytes are plants having vascular system containing well developed stem, root and leaaves.

    Answered by RAJENDRA SINGH (Mar 22, 2017 6:07 p.m.)
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In a compound of ammonia, nitrogen and hygrogen are present in ratio 14:3 by mass. If actual mass of hydrogen is 9g, then what would be the actual mass of nitrogen present in it?

 

Posted by Jaimini Patel (Mar 22, 2017 12:43 p.m.) (Question ID: 4388)

  • Answers:
  • Ans. Ratio = 14: 3

    Let Nitrogen = 14x

    Hydrogen = 3x

    Given, 3x = 9

    x = 3

    So Nitrogen = 14 *3 = 42g

    Answered by Naveen Sharma (Mar 22, 2017 5:15 p.m.)
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Tips of pens are pointed and narrow?Why

Posted by Anand Sharma (Mar 22, 2017 12:32 p.m.) (Question ID: 4387)

  • Answers:
  • because of capillary action ink moves towards tip

     

    Answered by Devesh Singh (Mar 22, 2017 1:21 p.m.)
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What is eutrophication?

Posted by Manoj Dwivedi (Mar 21, 2017 10:19 p.m.) (Question ID: 4362)

  • Answers:
  • Ans. Eutrophication is enrichment of ecosystem with chemical nutrients mostly by compounds of Nitrogen and Phosphorus is called Eutrophication. It results in growth of algae in water and deteriorates the water quality.

    Answered by Naveen Sharma (Mar 22, 2017 7:24 a.m.)
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Where is the otba theam for class 9th sub:- science topic:- conservation of water bodies

In app version of this site

Posted by akash suryavanshi (Mar 20, 2017 10:15 p.m.) (Question ID: 4269)

What is matter

Posted by Lucky Boy (Mar 20, 2017 10:04 p.m.) (Question ID: 4267)

  • Answers:
  • all matter are made of very small particals called atoms ... full ans are available in class 9th A5 of Deepak memorial academy ..

    Answered by akash suryavanshi (Mar 20, 2017 10:18 p.m.)
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What is hydro bios????

Posted by Shalini Jha (Mar 20, 2017 7:49 p.m.) (Question ID: 4238)

A and b are two elements with the following sub atomic particles 

A- protons 8, neutrons 8

B- protons 8, neutrons 9

 

Posted by Akshit Dhot (Mar 20, 2017 7:20 p.m.) (Question ID: 4233)

  • Answers:
  • When two elements have same number of protons but different number of neutrons, they are said to be isotopes.

    In this question, we have 168O and 178O as the isotopes of Oxygen.

    Answered by Shweta Gulati (Mar 20, 2017 8:04 p.m.)
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Write four convenstions to be followed while writing the scientific names of the organisms. Write the scientific name of tiger. 

Posted by Akshit Dhot (Mar 20, 2017 7:17 p.m.) (Question ID: 4232)

  • Answers:
  • Ans. Rules/Conventions followed while writing the scientific names are:

    • The generic name/genus should start with a capital letter.
    • The species name should start with a small letter.
    • The names should be underlined separately when written by hand.
    • When printing, the scientific name should be written in italics.

    The scientific name of tiger is Panthera tigris.

    Answered by Naveen Sharma (Mar 20, 2017 8:15 p.m.)
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  • Only panthera tigers 

    Answered by Akshit Dhot (Mar 20, 2017 7:49 p.m.)
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  • panthera tigris

    Answered by Innocent Geeta (Mar 20, 2017 7:43 p.m.)
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What does 'source reduction 'and 'source separation 'imply? 

Posted by Akshit Dhot (Mar 20, 2017 7:14 p.m.) (Question ID: 4230)

  • Answers:
  • Source reduction, also known as waste prevention or pollution prevention, is the elimination of waste before it is created. Source reduction is decreasing the amount of materials or energy used during the manufacturing or distribution of products and packages. 

    Sorting of different materials comprising a waste (such as glass, metals, paper, plastics) at its point of generation, for a simpler and more efficient recycling or final disposal. It is called as Source separation.
     

    Answered by Shweta Gulati (Mar 20, 2017 8:11 p.m.)
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