General Knowledge Thread.

[Ankurbaliyan]

There is a small correction.....There is no polarisation concept in case of microwave specially when we are dealing with conductors....Its come when we have dielectric....and Al is a good conductor....The sparking is basically because of the penetration depth of Electromagnatic Waves.....Higher is the frequency lower is the penetration depth...so the charge remain on the surface of the conductor....There reaches a stage when charge start to discharge via discharge current with atmospheric gases....if you have vaccum in the microwave then you will not have any discharge and in that case it willbe a faraday cage....

Microwaves produce a flow of current in foil.it sparks due to polarisation of highly charged particles and a conductor between them(alluminium). if particles(atomes,molecules) not polarised then foil simply burns without sparking..

yahi laga mujhe to isa explanation... phuysics padhe hue 1 decade ho gya.. sahi reason kya hai ye aap bta do..

[akshaymalik84]

Rakeshjee, padhnae ki koi umar nahee hotee - aab padh lo - B.Sc Physics mae admission mil jayeega aapko.

Regards,

Urmila.

क्यूँ Einstein और Newton की थेओरी फ़ैल करवान पे तुल रहे हो आप ......:rock:rock

[Ankurbaliyan]

This is true that room will not be cooled....the reason is this is aganist the third law of thermodynamics....also known as entropy....the entropy is always conserve for the closed system...

Rakeshjee, exact reason toh shayed mujeh aab nahin pata-12th class mein kabhi padha tha- compressor maybe generating more heat to cool the air of the room.

Regards,

Urmila

[htomar]

u r right... sparking happens only when there are sharp edges in metal... if it is thik and have no sharp edge then no sparking.

There is a small correction.....There is no polarisation concept in case of microwave specially when we are dealing with conductors....Its come when we have dielectric....and Al is a good conductor....The sparking is basically because of the penetration depth of Electromagnatic Waves.....Higher is the frequency lower is the penetration depth...so the charge remain on the surface of the conductor....There reaches a stage when charge start to discharge via discharge current with atmospheric gases....if you have vaccum in the microwave then you will not have any discharge and in that case it willbe a faraday cage....

[htomar]

entropy conserves for closed system,but here room is not closed completely(though it seems closed).
heat (basicaly in the form of electricity) is coming inside.

This is true that room will not be cooled....the reason is this is aganist the third law of thermodynamics....also known as entropy....the entropy is always conserve for the closed system...

[Ankurbaliyan]

There comes the concept of localized closed systems and globlized system....Room is considred to be closed system....Let me explain more....This closed system is similar to the Isothermal process.....where no heat exchange involve when you work on a pump.....if you work on a pump then it will generate heat for sure....but if you pump very slowely then it will not generate heat....so system now can be address as isothermal though when you do fast pumping then you have heat exchange invloved and sytem is no longer isothermal....similar to the this concept.....you have to consider the room is a closed sytem where there is no heat exchanged involved...and in the worst case if you want to involve the surrounding area of the room...then there will be a new concept called Entropy of the universe + its surrounding.....which is again conserve....second point.... Heat is not coming inside in the form of electricty...rather...heat will generate b/c of the compression...which is basicaly work on second law of thermodynamics....here refigrator is receiving the heat from the system and doing work while receiving the heat, on the expence of supplied electricty.... Hope this help....

entropy conserves for closed system,but here room is not closed completely(tohough it seems closed).
heat (basicaly in the form of electricity) is coming inside.

[htomar]

Ankur i understand your explaination..but my point is different here.
When we open the refrigerator in a closed room. cool air of Refrigerator mixed with hot air of room(heat transfer).
so refrigerator try to cool down the air.. as compressor consume more electricity to cool the air.so more heat generated.

There comes the concept of localized closed systems and globlized system....Room is considred to be closed system....Let me explain more....This closed system is similar to the Isothermal process.....where no heat exchange involve when you work on a pump.....if you work on a pump then it will generate heat for sure....but if you pump very slowely then it will not generate heat....so system now can be address as isothermal though when you do fast pumping then you have heat exchange invloved and sytem is no longer isothermal....similar to the this concept.....you have to consider the room is a closed sytem where there is no heat exchanged involved...and in the worst case if you want to involve the surrounding area of the room...then there will be a new concept called Entropy of the universe + its surrounding.....which is again conserve....second point.... Heat is not coming inside in the form of electricty...rather...heat will generate b/c of the compression...which is basicaly work on second law of thermodynamics....here refigrator is receiving the heat from the system and doing work while receiving the heat, on the expence of supplied electricty.... Hope this help....

[ravinderjeet]

Rakeshjee, padhnae ki koi umar nahee hotee - aab padh lo - B.Sc Physics mae admission mil jayeega aapko.

Regards,

Urmila.

यु तो पुन्झअड़ लावन की एमबीए करण लाग्र्या स |

[anilsangwan]

Bhai, Fridge ne thaa ke taang dyo khidki mein....... uska paachhla hissa kar dyo khidki tein baahar.......... uska kiwaad khol dyo kamre mein......... saari garmi baahar jaagi er thandak andar............... AC aala kaam karega fer woh Fridge... Poore ghar ne seela kar dega.................naa kare to try kar ke dekh lyo...

Ankur i understand your explaination..but my point is different here.
When we open the refrigerator in a closed room. cool air of Refrigerator mixed with hot air of room(heat transfer).
so refrigerator try to cool down the air.. as compressor consume more electricity to cool the air.so more heat generated.

[rakeshsehrawat]

Bhai, Fridge ne thaa ke taang dyo khidki mein....... uska paachhla hissa kar dyo khidki tein baahar.......... uska kiwaad khol dyo kamre mein......... saari garmi baahar jaagi er thandak andar............... AC aala kaam karega fer woh Fridge... Poore ghar ne seela kar dega.................naa kare to try kar ke dekh lyo...

Freeze bya jaga. Compressor khindta handega kade AC bana de.

Duhan ji dakhla karwa dyo mein college aale raste pe bhi chala jaun to ghar aali ghane e sawal pooch le hai (maslan ke dekhan gaye the? yu e rah paya baaki pe jam lag rehya tha wagarah wagarah)

[urmiladuhan]

Bhai, Fridge ne thaa ke taang dyo khidki mein....... uska paachhla hissa kar dyo khidki tein baahar.......... uska kiwaad khol dyo kamre mein......... saari garmi baahar jaagi er thandak andar............... AC aala kaam karega fer woh Fridge... Poore ghar ne seela kar dega.................naa kare to try kar ke dekh lyo...

good idea!!!

[urmiladuhan]

Freeze bya jaga. Compressor khindta handega kade AC bana de.

Duhan ji dakhla karwa dyo mein college aale raste pe bhi chala jaun to ghar aali ghane e sawal pooch le hai (maslan ke dekhan gaye the? yu e rah paya baaki pe jam lag rehya tha wagarah wagarah)

Rakesh jee, wife ko bhi apnae saath admission deela daena! Dono saath saath class mae jana, baithna, home work karna, exam kae leeyae padhna - aapsee prem aur badh jayeega!!!

Regards,

Urmila.

[urmiladuhan]

Another question:

Sprinkling of common salt on roads with ice sheet/snow on them, leads to what and why?

Regards,

Urmila.

[urmiladuhan]

Another question:

Milk obtained directly from the animal, if boiled and stored, gives more cream on the milk surface than dairy processed milk, even though no addition/removal of fat has been done at the dairy. Why so?

Regards,

Urmila.

[anilsangwan]

Homozinised er pasturised ho s woh...... uska daliyaa kaadh dein s milk plant ki machine..........

Another question:

Milk obtained directly from the animal, if boiled and stored, gives more cream on the milk surface than dairy processed milk, even though no addition/removal of fat has been done at the dairy. Why so?

Regards,

Urmila.

[anilsangwan]

Baraf mein gaadi koni thisallti uss ke kaaran............

Another question:

Sprinkling of common salt on roads with ice sheet/snow on them, leads to what and why?

Regards,

Urmila.

[anilsangwan]

Er je Rakesh ke 1 number bhi faaltu aa gya exam mein to iski khair nahi............ Ujadwaa dyo ghar bechaarey ka...... isi general knowledge ka ke karengey hum jab ghar e ujadd jaaga !

Rakesh jee, wife ko bhi apnae saath admission deela daena! Dono saath saath class mae jana, baithna, home work karna, exam kae leeyae padhna - aapsee prem aur badh jayeega!!!

Regards,

Urmila.

[urmiladuhan]

Homozinised er pasturised ho s woh...... uska daliyaa kaadh dein s milk plant ki machine..........

How that that affect the cream layer thickness on top of the milk, Anil jee?

Regards,

Urmila.

[VirJ]

To lower the melting point of Ice. It isnt very helpful when temperature falls 'very low'.

Gadi na tisle uske liye "snow chains" use kara kare hen.

[urmiladuhan]

Baraf mein gaadi koni thisallti uss ke kaaran............

Salt does not provide anti skid property, per se. There is an alternate explanation (think about freezing point of water).

Regards,

Urmila.