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Test Papers – State Board Commerce (XI-XII) 2017-04-18T04:54:26+00:00

State Board Commerce (XI-XII) - Test Papers

State Board Commerce (XI-XII) - Test Papers

CLASS XII MH – PCMB Chemistry-Solid State Demo Videos

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Hello everyone we are beginning with a new chapter of your chemistry paper one that is solid state and in this particular module we are going to discuss definition of matter and its type and also we are going to cover characteristic of solids now whatever we see around us say from the point or television set to a point of an LCD player to that off of wooden door to that up in laptop or cold drink  or a steaming coffee to that of vehicle which is moving on the road or a plane which is moving in the air to that of the fume which is coming from the vehicle all of them fall into any simple term called as matter what i say that matter has three simple states of which the first one is solid the second one is liquid and a third one is gases if I talk about the example that a simple example of a solid as ice that liquid is water and out that of the gases steam and from the previous knowledge which we have we are aware that solids on heating convert to liquid, liquid on further heating converted to gas gases on cooling turns to liquid and liquids on further cooling turns two solids now let’s have a look at each of the example of each of the conversion in detail the first example shows you that conversion of solid into liquid that is precisely melting of ice this particular part will show you a water cycle where you will address that the water from the sea evaporates, evaporates to give you a cloud the cloud becomes dense and once again it comes in the form of rain and the here I see the first process is nothing but liquid to gas conversion and the second one is gas to liquid conversion  also if I talk about one more example the Near you will observe conversion of liquid into solid that’s one more exam full conversion of liquid into solid so you’re we saw the inter conversion of solid to liquid ,liquid to gas, gas to liquid and liquid to once again solid and if the question is – how does three states of matter inter convertible and the answer is simple that is intermolecular force of attraction and your eyes say that the physical state of matter is the result of interplay of intermolecular force of attractions like dipole-dipole interaction dipole induced dipole interaction London forces and hydrogen bonding and there are many more but this is the reason for the Inter conversion of three states of matter precisely if I talk about solids then in solids the intermolecular force IMF is the strongest in case of liquid the intermolecular force of attraction is moderate and in case of gases the inter molecular forces of attraction is weak we’re in case of solids if I talk about the mass shape density volume let’s talk about that in case of solids they have a definite shape they have a definite mass they have a definite volume and they have a definite  Density  where is a in case of liquids they have a definite mass they have a definite volume and density but they have an in definite shape we’re in case of gases they have in definite volume in definite density and in definite shape that’s a possible thing which you should know about this three states of matter out of the three states of matter that is solid liquid and gases liquids and gases already we have discussed in 11 standard chapter that the states of matter so right now you’re we are going to discuss solid state in detail so let’s start with the first part of the chapter that is characteristics of solids the first point say is that solids of fixed composition will have fixed mass volume shape and density solids or fixed composition will have fixed us volume shape and density the second characteristic solid is that the in case of solids the intermolecular distance is Dash(-) let’s try to answer this let’s have a look into this particular solid and if you look into the solid if you peep inside the solid will observe that the arrangement of particles let’s magnify that the arrangement of particle is very close and hence we say that the distance the distance the intermolecular distance in case of solids is very short the distance is the shortest now why the distance is the shortest is just because the Intermolecular our force of attraction is very strong and because the distance is very short and the intermolecular force of attraction is very strong we say that solids are hard they are rigid and they are in compressible let’s have a look at the last characteristics of solids the last characteristics or solids precisely talks about something called as the position and motion if you have a look at this particular arrangement and if I ask you what exactly is the position than the particles have a fixed position and if you have a look at the motion of the particles in the particles are in a vibratory motion they are in an oscillating motion so here I say the position is fixed and the motion vibratory and hence i conclude with my last characteristics of solid by saying that the Constituent particles and solids have fixed position and vibrantly motion that’s all we have for this particular module thank you so much.

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CLASS XII MH – PCMB Chemistry- Aldehydes Ketones Acids Demo Videos

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Hello students we are starting with the most interesting chapter of 12 standard chemistry paper to the name of the chapter  is aldehydes ketones and carboxylic acid students we are going to study this chapter in modules in this particular module we are going to discuss introduction and definition of a carbonyl group followed by classification of a carbonyl group and finally we are going to a structure of a carbonyl group so you’re we go with the first point that’s the introduction  is wooden you know you can see one statement on a screen as aldehydes and ketones are known as carbonyl Compounds now student you may have got a thought what our carbonyl compounds the answer is a carbonyl compounds are those compounds which contains carbonyl group now students if you can see there is one more term what is carbonyl groups on a screen you can see a group which is actually a carbonyl group now student let’s do a little bit detailing of this particular group so you’re student can you see carbon atom of this group is sp2 hybridized one more point has to be discussed in this the carbon atom of this particular group is known as carbonyl carbon and the oxygen atom of this group is known as carbonyl oxygen so student this was just a brief introduction let’s now the final carbonyl group so students can you see over your a carbon atom is attached to an oxygen bar double bond  not only this it is what one more feature can you see that two single bonds attached to a carbon atom that is nothing but what these two valence are actually free so if you combine both these statements you can define what is a carbonyl group so a group in which a carbon atom is attached to oxygen by a double bond and remaining two valence of a carbon atom are free is known as carbonyl group student this was just the introduction let’s move on to the next topic that’s a classification so you’re sort of we have got a carbonyl group know There are total to in all three basic compounds where the carbonyl group is Present Here the first one I have got a carbonyl group one side of the carbonyl group is an alkyl group are on the other side you have got another group called H these type of compounds are called as are the aldehydes the second compound  again I have carbonyl group one side of the carbonyl group if I’ve got alkyl group and on other side also if I have got an alkyl group maybe same Or may be different  these type of compounds are called as ketones  finally the third 1 i have got Over here a carbonyl group one side of the carbonyl group I would an alkyl group on the other side of the carbonyl  and group I’ve got on hydroxyl group which is OH group the type of compounds are called as carboxylic acids student Remember in all there are four more compounds where carbonyl group is present but since those compounds are obtained from carboxylic acids so we know them as Substituted acids  let’s go in detail of those compounds so you’re I’ve got the first compound where it you can see a carbonyl group one side if you have an alkyl group on the other side if you have got an or our group which is called as alkoxy group these type of compounds are called as ester similarly I have got a carbonyl  Group one side of the carbonyl  have got an al alkyl group on the other side i have gotten halogen which is X these type of compounds are called as us acyl Halide then the next one again I have got a carbonyl Group one side if you see that is an alkyl group Other  side  that an nh-2 group that’s an amine group these type of compounds are called as amides finally I have got a group whereas to carbonyl group in between that is one oxygen atom either side of the carbonyl groups if I’ve got an alkyl group may be same or different these type of compounds are called as acid anhydride so student these last four compounds what we discussed they are as acid derivatives the student remember one thing out of the seven Compounds  what you can see first two compounds are only known as carbonyl compounds and rest of those five they are not a carbonyl compounds since they have a carbonyl group but did not behave as a carbonyl  group and the reason is due to resonance which we are going to discuss later on so you’re we end up with the classification let’s move to the next topic that’s a structure of a carbonyl group so you’re on the screen I have got a carbonyl group there you have a lone pair on oxygen atom if you see the Carbon atom  and remember it’s sp2 hybridized and the bond angle would be nothing but 120 the geometry of this group will be nothing but triangular planner  in our or we can call it as triangular planner are not only this one more point students a carbon atom if you see there are two single bonds single bonded they are Sigma bonds and between that carbon oxygen if you see one of the bond is Sigma and the second-bond is nothing but a PI bond so student  this is something what we are going to discuss or we had discussed in this particular module thank you very much.

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CLASS XII MH – PCMB Biology -Gene Demo Videos

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Hello students now let’s talk about the fifth part of the semi conservative replication of DNA here I were talking about the fourth step of replication which is called as synthesis of new strands that ok let’s start a look at this picture what do you see you guessed it right this was the same picture from the previous module we call it as the replication fork yes fine let’s check the orientation of the two strands one is reading from three prime to 5 frame and the other one is we read from three prime to 5 prime in the opposite direction is that ok now let’s bring back an enzyme here look at that enzyme what is this enzyme you know it it is DNA helicase that’s correct let us put the helicase into action and open the strength some more there you go and voila once again what did you see you simply saw the two strands of DNA now got almost completely Separated yes correct now let’s check the orientations once again you have the three prime five prime and you have the three prime five prime in the opposite direction for the two strands right now these both single strands can act as a template for synthesizing new strands is that okay for right now I’m going to just look at the left strand as a Template let us see how does this template strand make a new strand on itself right now for the purpose of replication we require a molecule called as RNA primer Right look at the name RNA primer what is a primer let’s see that a primer is a strand of shot on the sequence itself as a starting point for DNA synthesis right how cool is that you have an RNA but it synthesizes new molecule of DNA is that ok fine now this on the primer is synthesized by a special enzyme not shown here called as RNA primase so please remember RNA primer is synthesized by RNA primer the enzyme right now look at that are the primer carefully look at that symbol yellow right you know that if it was all arranged that would be thymine and that would be DNA but this is RNA so i changed the color to yellow and that yellow is what Uracil so and that’s why you know that is an RNA primer now what is this primer really really do let us see that next now this primer is known to attach to the three prime end of the template strand using the template strand yes you do do you see the three prime end now you do is that ok so let’s take the honor primer and put it on the three prime end of the template strand what would you do after getting attached there let’s see that next now these primers are known to attract complimentary nucleotides from the nucleoplasm let us see how it would do that look at that what do you see it is attracting complimentary nucleotides from the nucleoplasm and they should be complementary to what they should be complementary to the bases on that template strand but now it requires another enzyme to build that new strand let’s see what that enzyme, that enzyme is called as DNA polymerase remember DNA polymerase is the main replicating inside because it will replicate or to make the new strand of DNA and let us see how it would do that ,that’s the polymer is here it is scanning the template and it is adding the complementary base pairs and building up the new strand you can see how that is happening right look carefully yes i’m going to go ahead some more then again i’m going to add new bases in my new strand that a complementary to the template strand some more ahead some more bases so that’s what DNA polymerase does it scans the template and it keeps adding the nitrogen bases right complementary to the template strand ok now i have built a new strand i’m going to call this the new strand synthesized from five prime to three prime direction and this is how synthesis of new strand takes place notice something you’re very importantly the new strand of DNA is always synthesized from five prime to three prime direction which means the template strand should always be oriented from three prime to 5 prime direction you have to make note of this very important ok and this brings us to the end of the module number five on semi conservative replication of DNA in the next module I were talking about the sixth part of the semi conservative replication of DNA thank you and take care.

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CLASS XII MH – PCMB Biology-Human Reproduction Demo Videos

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Hello students in this module we are learning an important process call as fertilization or syngamy now let’s see what this beautiful process is then we want to define fertilization students it is the process of what of fusion of haploid meal and female gamete to form what to fall deployed zygote with to n chromosomes students so this is what the definition of fertilization is but let’s do the detailing of fertilization when we talk about fertilization and human students it is internal that means it takes place inside the body of the female but very exactly inside the body of the female it takes place here and what is this point being pointed at this is the ampulla of the oviduct  like the longest section oviduct  fertilization occurs in the ampulla of oviduct and normally within the six hours of ovulation students now when we talk about fertilization millions of worms released during the insemination that is the release of semen in the vagina of the female around 300 million sperms released but only very few i capable of getting close to the egg and from those few only one gets to fertilize students and let’s see when we talk about fertilization after insemination activation of sperms takes place by Fallopian tube which releases of this viscous fluid but another important step before the actual process of fertilization takes place students is something we call as fertilizing , ant fertilize in reaction and what is that let’s see now what happens is the ovum-female ovum has a glycoprotein which secrete scholars fertilizing it recognized this human sperm because human egg needs to be fertilized by human sperm only so this chemical students recognizes another chemical on the sperm head which is call as antifertilizing which is produced by sperm head and once it recognizes that then only fertilization can proceed this process is one of the most important process before the fertilization callers fertilizing antifertilizing reaction students which is Highly, highly species-specific that means the sperm of any other organism any other animal cannot fertilized human egg now moving on to the details of the process students this is a human egg and let’s say the sperm  which is trying to fertilize the Egg it has to penetrate or pass through three less outermost corona radiate then the second one the transparent ones zona pellucida and inner most students is the vitalline membrane to it needs to penetrate through these three layers and then only fertilization will be successful so let’s see the first layer corner radiator how does it pass through this it releases an enzyme a chromosome of the sperm students releases an enzyme called as Hyalurronidase  acid  which dissolves the cells of this layer remember corona radiate ourselves students were glued by the acid called Hyalurronidase acid that Hyalurronidase acid  is destroyed by this enzyme called as Hyalurronidase  now the second layer which is that zona pellucida, zone pellucida  students has penetrated by the release of an enzyme called as a acrosin or zona lysin that dissolves this layers are two barriers cross now the third is which one  vitalline membrane  students was the sperm head the achromosome membrane touches the vitalline membrane the fuse together a Achrosome membrane the membrane and vitalline membrane fused together and that releases the nucleus of sperm inside the plaza  immediately after the students second meiosis  completes you remember egg of the female was arrested at metaphase 2 stage of meiosis to now it proceeds further and meiosis to complete so you can see that now there are two polar bodies that know by this time first polar body also divides to form another polar body so in the parry vataline Space you may see two or three polar bodies there now what happens after simultaneously with this is the vatelline membrane you can see transforms into a membrane which we call as the fertilization member and what is the purpose of that once fertilization membrane is form students No other sperm can penetrate through the egg now that means fertilization membrane is preventing polyspermy no other sperm can penetrate through the Egg now what happens to this is both the nuclear sperm nucleus and egg nucleus they absorb lot of water and they start growing inside and see that we call them Now pro nuclei sperm pronucleus fuses with the egg pronucleus we call this process as amphimixes or karyogoma. Karayo nuclious Gamy is marriage and students this is when we see a woman has conceived or she is pregnant now fertilization significance what for fertilization complete oogenesis it also determines the gender of the baby if the sperm having X chromosome fuses it’s going to be a baby girl and if it is y chromosome it’s going to be a baby boy also it restores diploydi the fertilization in turn was this proximus centriole  or in the ovem  also students it brings about genetically combination leading to Variation and the most important processes evolution so here then we completed fertilization students we are going to be the next module taking care of embryonic development until then take care.

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State Board Semi English Std IX Geometry Demo Videos

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StateBoard_Semi_English_Std_IX Sanskrit Grammar Demo Videos

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