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Thu July 31, 2014  

Ans: Dear whitestone7587@gmail.com

Thanks for asking us a question in Ask the Expert section of TopperLearning.com.
A similar question is already been answered, please refer the already answered questions.

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Topperlearning Team.

Thu July 31, 2014  

Ans: A neutron is made up of two down quark and one up quark so net charge will be (-1/3 e) + (-1/3e) + (+2/3e) = (-2/3 e) +(+ 2/3e) = o which indicates that neutron is nuetral.no charge as such.

Thu July 31, 2014  

Ans: Dear whitestone7587@gmail.com

Thanks for asking us a question in Ask the Expert section of TopperLearning.com.
Same question is already been answered, please refer the already answered questions.

Regards

Topperlearning Team.

Wed July 30, 2014  

Ans: Quarks are the fundamental constituent of matter and are the elementary entities(particles) that make up the subatomic particles like protons and neutrons.The quarks are assigned fractional electric charges of - 1/3 e (called the down quark, denoted by d) and + 2/3 e (called up quark, denoted by u).The proton is composed of three quarks(i.e.uud), two with charges of +2/3 e and one with charge of -1/3 e, which adds up to a net charge of + e .A neutron is made up of two down quarks and one up quark(ddu). Till now no isolated quark has been observed due to the exceptionally strong force called color force which prevents them from escaping.This force increses with seperation distance.

Wed July 30, 2014  

Ans:

Wed July 30, 2014  

Ans: Dear se_signal@yahoo.co.in

Thanks for asking us a question in Ask the Expert section of TopperLearning.com.
Syntax error from line 1 column 49 to line 1 column 69. Unexpected '<mi '.

Regards

Topperlearning Team.

Wed July 30, 2014  

Ans: Dear bujjimahesh@yahoo.com

Thanks for asking us a question in Ask the Expert section of TopperLearning.com.
We have not understood the query that you have posted. We would request you to clarify / provide additional details so that we may answer this to the best of the ability.

However what we have understood from your question is,   1) The size of void depends upon the size of the atoms. The size of tetrahedral void may be larger or smaller or equal to that of the octahedral void depending upon the size of atoms.  2) In a single crystal lattice, when the size of the atoms are same, then tetrahedral void is smaller as compared to octahedral void.   Regards

Topperlearning Team.

Wed July 30, 2014  

Ans: Glass has ability to flow as it is amorphous. It can be observed in the windows of old buildings. They are thicker at the bottom and thinner at the top. It shows that glass has the ability to flow which is normally showwn by liquids. Hence glass is reffered as super-cooled liquid.

Wed July 30, 2014  

Ans: Dear dubey.bharat7@gmail.com

Thanks for asking us a question in Ask the Expert section of TopperLearning.com.   1.Crystal structure of some elements is already determined and which is standard as it is determined by some experiments so we can consider their respective values in our calculations. 2.Two unknown parameters won’t be present in the problem, value of either parameter will be provided.
Regards

Topperlearning Team.

Wed July 30, 2014  

Ans: Crystallization PRINCIPLE- The process of formation of crystals from a hot saturated solution from cooling.This method is based on the difference in the solubilities of solids in a liquid. TECHNIQUE- This method in involves dissolving the mixture completely in water and heating this mixture. Further cooling of this mixture results in the formation of crystals of less soluble solid on the surface of the solution. The mixture is added to hot water and heated in a china dish to obtain a saturated solution. The mixture is then allowed to cool till the crystals are formed. DIAGRAM- EXAMPLE- Preparation of pure copper sulphate crystals in the laboratory.  Purification of salt that we get from the sea. Separation of crystals of alum from impure samples.

Wed July 30, 2014  

Ans: Hydrogen is the lightest element in the world as it has only 1 proton, 1 neutron and 1 electron.

Wed July 30, 2014  

Ans: Cockroaches belong to the class Insecta of the phylum Arthropoda. The scientific name for cockroach is Periplaneta americana . The length of an adult Periplaneta americana is 34–53 mm. The body of a cockroach is segmented into the head, thorax and abdomen. Sclerites are the hard chitinous plates which form the exoskeleton in cockroach. Tergites cover the body of cockroach ventrally while sternites cover the body of cockroach dorsally. Antennae in cockroaches have sensory receptors which help in monitoring the environment. The mouthparts found in cockroach are a labrum, a pair of mandibles, a pair of maxillae and a labium. Alimentary canal : Alimentary canal divides the body of a cockroach into foregut, mid gut and hindgut. Mouth opens into crop which is used for storing the food. Crop is followed by the gizzard. It helps in grinding the food. Gastric caecae present at the junction of foregut and mid gut secrete digestive juices. Hind gut is differentiated into ileum, colon and rectum. Rectum opens out through anus.   Excretory system : 100–150 Malpighian tubules are present in cockroach. They are present at the junction of mid gut and hind gut. Uric acid is the waste product formed at the end of the process. Hence cockroaches are uricotelic animals.   Circulatory system : The heart of a cockroach is a long muscular tube lying along the mid-dorsal line of the thorax and abdomen. It is differentiated into funnel-shaped chambers, and it bears ostia on either side. Blood from the sinuses enters the heart through ostia, and it moves anteriorly in the heart and is released into the sinuses again.   Respiratory system : The respiratory system of cockroach consists of a network of tracheae. Tracheae open outside through 10 pairs of spiracles which are present on the lateral side of the body. Tracheae are further divided into tracheoles which carry oxygen to all parts of the body. Exchange of gases occurs at the tracheoles by diffusion. The openings of spiracles are regulated by the sphincters.   Male Reproductive System : A pair of testes lying on the lateral sides of 4-6 abdominal segments. From each testis, a thin vas deferens arise which opens into an ejaculatory duct through seminal vesicle. Ejaculatory duct open into the male gonophore. Phallomere represents the external genitalia of the male cockroach.   Female Reproductive System : Female reproductive system consists of two large ovaries. Each ovary is formed of eight ovarioles. Oviducts of both the ovaries unite to form median oviduct. A pair of spermatheca is present in the 6 th segment which opens into the genital chamber.   Economic importance : Human homes are the habitats of cockroaches. Cockroaches thrive in and around human homes. They are pests because they contaminate food by their excreta and destroy it. Through contamination of food, cockroaches also transmit various bacterial diseases.

Wed July 30, 2014  

Ans: Given: P 1 = 800 mm of Hg
V 1 = 10000 L
T 1 = -3 o C = 273 - 3 = 270 K

P 2 = 400 mm of Hg
V 2 = Volume required for filling gases with New temp and pressure condition= ?
T 2 = 273 K

Let us apply combined gas law, We get,

P 1 V 1 /T 1 = P 2 V 2 /T 2 

V 2 = P 1 V 1 T 2 /T 1 P 2  

V 2 =(800 10000 × 273)/(270 × 400) = 20222 L of gas is to be filled

Thus no. of cylinders required = 20222/10                                           = 2022.2 (approx.) ......Ans.

Wed July 30, 2014  

Ans: Isotonic solutions:  If there are two solutions and the concentrations of solutes in both the solutions are same, then they are isotonic solution. Hypertonic solutions and Hypotonic solutions:  Consider, there are two solutions A and B. When solution A has higher concentration of solute than solution B, then solution A is called hypertonic solution. When solution A has lower concentration of solutes than solution B, then solution A is called hypotonic solution.  

Wed July 30, 2014  

Ans: The distance-time graph of a train standing on a platform will be a straight line on the time axis. Since, the train is stationary it does not cover any distance.  

Tue July 29, 2014  

Ans: At high altitude, atmospheric pressure is lower than that at sea level. At high altitude, atmospheric temperature decreases as pressure decreases.

Tue July 29, 2014  

Ans: F r o m space t h e space b a s i c space r e l a t i o n space b e t w e e n space i n t e g r a t i o n space a n d space d i f f e r e n c i a t i o n integral f to the power of apostrophe open parentheses x close parentheses space d x space equals space f open parentheses x close parentheses plus C  S o space i f space f to the power of apostrophe open parentheses x close parentheses equals 0 comma space w h i c h space m e a n s space w e space a r e space d i f f e r e n t i a t i n g space e i t h e r space a space c o n s tan t space t e r m space o r space z e r o space w i t h space r e s p c t space t o space x space w h i c h space i s space g i v i n g space u s space z e r o. space  rightwards double arrow A s space p e r space a b o v e space d e f i n i t i o n comma space w e space g e t space f left parenthesis x right parenthesis space a s space e i t h e r space z e r o space o r space s o m e space c o n s tan t space f u n c t i o n. space

Tue July 29, 2014  

Ans: Dear psmathew_p@rediffmail.com

Thanks for asking us a question in Ask the Expert section of TopperLearning.com.
We have not understood the query that you have posted. We would request you to clarify / provide additional details so that we may answer this to the best of the ability.   We dont have the reference book you have mentioned in email. Please post the question so that we can answer your query.

Regards

Topperlearning Team.

Tue July 29, 2014  

Ans: A strong acid will react with a weak base to form an acidic (pH < 7) solution.

Tue July 29, 2014  

Ans: I n space t h e space g i v e n space t r i a n g l e comma space i f space w e space j o i n space A comma space B space a n d space C space w i t h space O space a n d space c o n s i d e r space t r i a n g l e s increment O C E comma space O C squared equals O E squared plus C E squared increment O B D comma space O B squared equals O D squared plus B D squared increment O A F comma space O A squared equals O F squared plus A F squared  A d d space a l l space t h e space a b o v e space t h r e e space e q u a t i o n s comma space w e space g e t rightwards double arrow O C squared plus O B squared plus O A squared equals O E squared plus C E squared plus O D squared plus B D squared plus O F squared plus A F squared rightwards double arrow O C squared plus O B squared plus O A squared minus O D squared minus O E squared minus O F squared equals A F squared plus B D squared plus C E squared  C o n s i d e r space f o l l o w i n g space t r i a n g l e s comma space increment O C D comma space O C squared equals O D squared plus C D squared increment O B F comma space O B squared equals O F squared plus B F squared increment O A E comma space O A squared equals O E squared plus A E squared  A d d space a l l space t h e space a b o v e space t h r e e space e q u a t i o n s comma space w e space g e t rightwards double arrow O C squared plus O B squared plus O A squared equals O D squared plus C D squared plus O F squared plus B F squared plus O E squared plus A E squared rightwards double arrow O C squared plus O B squared plus O A squared minus O D squared minus O E squared minus O F squared equals A E squared plus C D squared plus B F squared
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