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NCERT Exemplar Solutions Class 6 Mathematics Solutions for Exercise in Chapter 4 - Fractions and Decimals

Question 12 Exercise

0.023 lies between

(A) 0.2 and 0.3

(B) 0.02 and 0.03

(C) 0.03 and 0.029

(D) 0.026 and 0.024

Answer:

(B) 0.02 and 0.03

0.023 lies between 0.02 and 0.03

Video transcript
hello students welcome to leader learning's question and answer videos my name is palin and i teach maths and science at lido let's have a look at this very interesting question that is what do you mean by anomalous behavior of water before we go ahead with the anomaly in water let's talk about liquids in general so thermal expansion in liquids we all know that thermal expansion happens in liquid that is the liquids they expand when provided heat now let's try to understand this phenomena in a bit detail let's say these are the this is how the molecules of liquid they look like a little further away from each other now what happens when we provide heat to the molecules or heat to the liquid in general the kinetic energy of the molecules increases as a result the intermolecular force of attraction between them will decrease so let me write that down so intermolecular forces of attraction start decreasing or decreases as a result the molecules will start moving farther away from each other as in this case so they start moving further away from each other therefore the liquid expands right but it doesn't happen with water so why does it not happen or what exactly happens let's just look at the answer here so why do what do we mean by enough behavior substances they expand on heating and their density decreases now we know the density is what density is mass by volume so here we talked about the molecule expanding right if they are expanding means volume is increasing if volume increasing is increasing the density will decrease so the substances they expand on heating and the density decreases but in case of water it might happen water does not expand between 0 to 4 degree celsius instead it contracts so water contracts between 0 to 4 degree celsius expands however above four degree celsius so let's say if this is the water at zero degree celsius this will be water at four degrees celsius that is density has increased right now this means that water has maximum density at four degree celsius and this is called anomalous behavior of water because just quite opposite to what happens in liquids now why this happens is you will study in your higher classes so we all know that water molecule h2o so what happens is when we start giving heat to the water molecules hydrogen bonds in the molecule of water they start breaking down and at four degree celsius all hydrogen bonds have broken down that is the result that is the reason why all the molecules they come close together or the density increases but if we continue providing heat to the water then it follows thermal expansion the normal thermal expansion which happens in liquids that is the molecule moving further apart and the forces of attraction between the molecules is reducing is increasing sorry reducing so that is what happens if you have any further questions please post your comments below do not forget to subscribe to lido thank you
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