Learn periodic table in just 25 minutes in punjabi .

you can learn the complete chapter in just 25 minutes.

Which of the following lattice has the highest packing efficiency? (i) simple cubic (ii) bodycentred (iii) hexagonal close packing.

Packing efficiency of all these kind of arrangements is given as follows. (i) Simple cubic :- Its packing efficiency is 52% . (ii) Body centred cubic :- Its packing efficiency is 68%. (iii) Hexagonal close packing:- Its packing efficiency is 74% . Conclusion :- From the above data we can conclude that hexagonal close packedContinue reading “Which of the following lattice has the highest packing efficiency? (i) simple cubic (ii) bodycentred (iii) hexagonal close packing.”

What is myopia near sightedness class 10th cbse pseb board classes

This is a type of eye defect Near sightedness or Myopia is a defect of eye in which the objects present near can be seen clearly but the far ibjects can not be seen by the person suffering from this disease. It can arise due to the following reasons :- 1. Increased length of eyeContinue reading “What is myopia near sightedness class 10th cbse pseb board classes”

What is rancidity ? Why the packets of chips and fries are flushed or filled with nitrogen gas while packing?

It is the foul smell produced by the oxidation of oils and nuts. Mostly the bitter taste of peanut and food made by frying is due to rancidity . Normally the oily substances which are not covered properly , react with the oxygen of air and get oxidised thus give a foul smell. Removal ofContinue reading “What is rancidity ? Why the packets of chips and fries are flushed or filled with nitrogen gas while packing?”

Why should a magnesium ribbon should be cleaned before burning in air?

Magnesium is a reactive metal, it reacts with the oxygen of air and forms magnesium oxide. Magnesium oxide makes a layer on the upper surface of the metal. Which makes it difficult for the magnesium to get burnt and give characteristic flame. By using sandpaper we can remove its upper layer for proper combustion reactionContinue reading “Why should a magnesium ribbon should be cleaned before burning in air?”

The electrons that gain enthalpy for metals is positive and negative for non metals. Also, if metals are bigger in size than non metals then, how can electrons gain enthalpy is inversely proportional to the atomic size?

The answer is simple, like you are hungry you can pay more to get the food than that of the person who is less hungry, Similarily here the non metals want electrons thus they spend the energy more , or they release the energy. By this they lose the energy. So smaller is the sizeContinue reading “The electrons that gain enthalpy for metals is positive and negative for non metals. Also, if metals are bigger in size than non metals then, how can electrons gain enthalpy is inversely proportional to the atomic size?”

ਪਾਠ 10

page number 181 1  ਅਵਤਲ ਦਰਪਣ ਦੇ ਮੁੱਖ ਫੋਕਸ ਦੀ ਪ੍ਰੀਭਾਸ਼ਾ ਦਿਓ  ।ਉੱਤਰ :- ਅਵਤਲ  ਦਰਪਣ ਦਾ ਮੁੱਖ ਫੋਕਸ ਉਹ ਬਿੰਦੂ ਹੁੰਦਾ ਹੈ ਜਿਸ ਉੱਤੇ ਦਰਪਣ ਤੇ ਟਕਰਾਉਣ ਤੋਂ ਬਾਅਦ ਪ੍ਰਕਾਸ਼ ਦੀਆਂ ਕਿਰਨਾਂ  ਮਿਲਦੀਆਂ ਹਨ ਜਾਂ ਮਿਲਦੀਆਂ ਹੋਈਆਂ ਪ੍ਰਤੀਤ ਹੁੰਦੀਆਂ ਹਨ 2 ਇਕ ਗੋਲਾਕਾਰ ਦਰਪਣ  ਦਾ ਵਕਰਤਾ  ਅਰਧ ਵਿਆਸ  20 ਸੈਂਟੀਮੀਟਰ ਹੈ  ਉਸ ਦੀ ਫੋਕਸContinue reading “ਪਾਠ 10”

ਅਵਤਲ ਦਰਪਣ ਦੇ ਮੁੱਖ ਫੋਕਸ ਦੀ ਪ੍ਰੀਭਾਸ਼ਾ ਦਿਓ ।

ਉੱਤਰ :- ਅਵਤਲ  ਦਰਪਣ ਦਾ ਮੁੱਖ ਫੋਕਸ ਉਹ ਬਿੰਦੂ ਹੁੰਦਾ ਹੈ ਜਿਸ ਉੱਤੇ ਦਰਪਣ ਤੇ ਟਕਰਾਉਣ ਤੋਂ ਬਾਅਦ ਪ੍ਰਕਾਸ਼ ਦੀਆਂ ਕਿਰਨਾਂ  ਮਿਲਦੀਆਂ ਹਨ ਜਾਂ ਮਿਲਦੀਆਂ ਹੋਈਆਂ ਪ੍ਰਤੀਤ ਹੁੰਦੀਆਂ ਹਨ ।