Physics problem

[Aly Emran]

why does fuse blow even when the casing is earthed and how to remember deflections of alpha beta? Plus how to know that one energy is changing into other like PE into KE/ or heat and why does liquid donot expand?? thanks in advance

 

[Osaid Zahid]

For the First Question when the metal case becomes live and the live wire is connected to the casing . The casing is live and if it is earthed The current directly flows from the live wire to the earth via the metal case. Now since the main circuit of the appliance is bypassed the resistance of this connection is largely reduced. Hence a large cureent flows with overheats the fuse and it blows

 

[Osaid Zahid]

Alpha beta deflections in a an electric or magnetic field can be easily determined by the Fleming's left hand rule...Heat does not expand because there are strong forces between liquid particles and molecules and when these particles are energetic enough .. instead of expanding they escape into gaseous form

 

[Mustafa Malik]

i have a question : if a gas sealed in a container is heated , will the average distance bw molecules increase? I have a topical n it says no cuz there is no change in its state so.... though i think distance shud increase?

 

[Osaid Zahid]

Can Some one also answer this ..... We know that there in A/C circuitry there is live and neutral Wires in a switch board ... But have you noticed that when we plug in those two pin appliances you can really place then any way around...Doesn't Live and neural matter here .... There might be a rectification bridge if the appliance is DC... but what about those bulbs that work completely on AC supply. and why why electromagnetic waves are easily absorbed when their wavelengths are short and they are at high frequencies.....like Gamma rays ... they are dangerous while radio waves can easily pass through atmosphere without being absorbed too much...
also when Beta rays emits from a radioactive from a source the neutron splits electron files away and +ve charge is left behind how is that charge neutralized.

One last thing when a current flows through a How does a circular magnetic field at 90 deg just from around moving electrons...

 

[Osaid Zahid]

i have a question : if a gas sealed in a container is heated , will the average distance bw molecules increase? I have a topical n it says no cuz there is no change in its state so.... though i think distance shud increase?

Pressure definitely increases ... Molecules more and more with higher kinetic energies....The molecular distances should increase and would increase if it wasn't in an Enclosed container... The gas evenly spreads out and has occupies the volume OF the container and when the gass is heated the molecuse move more trying to get away but they cant so they exert pressure ... on the walls of the container... so no the distances between then Can't increase any more ...

 

[Osaid Zahid]

i didnt understood last line can u plz explain in detail. thanku

No problem you see the all the Current directly flows through the Fuse hence there is no resistance ... No resistance means the Fuse will have more current more going through it then it was designed for ... do like if fuse is 13 A No R means the Fuse has all potential difference across say and say a current of 15 A will pass so fuse is likely to blow

 

[Osaid Zahid]

i didnt understood last line can u plz explain in detail. thanku



but i read that liquid and gases expands !

Yes liquids expand they expand as much as the intermolecular forces can bear before escaping into gaseous state and they are poor conductors of heat.... Energetic liquid particles on the surface escape into a gas lowering the aveerage liquid temp ..and that is how evaporation works ... You water expands when cooled a special case due to hydrogen bonding and is densest at 4 degrees Celcius not 0.

 

[Osaid Zahid]

for ac idk about it but gamma rays have high penetrating power but low ionization power so they can go deep without being absorbed as short waves have high penetrating power. The nucleus contain protons and neutrons and the overall charge of nucleus is positive they r not neutralised. for the last qstn i didnt get it maybe qstn is not completed

Ok thanks my question was what makes then penetrating rays ? Short wavelengths maybe ? They are ionizing b/c they are completely energy.... .. about the radatiton Question i ment how does the atom the dauther nuclide itself become stable if it has an extra proton so Electrons not equal to protons ..... Last Q Why magnetic field froms around moving current ?

 

[Osaid Zahid]

i got it but a little problem why would R decrease

Sorry what i ment was there will be NO resistence

 

[Osaid Zahid]

a qstn
Liquid is being heated what is true about it?
a. liquid expands
b. molecules move further away

I Guess both

Key concept for Kenetic Therory... Same can be applied for liquids

• In a solid, the atoms are very attracted to one another. The atoms vibrate but stay in fixed positions because of their strong attractions for one another.
• Heating a solid increases the motion of the atoms.
• An increase in the motion of the atoms competes with the attraction between atoms and causes them to move a little further apart.
• Cooling a solid decreases the motion of the atoms.
• A decrease in the motion of the atoms allows the attractions between atoms to bring them a little close together.

 

[Osaid Zahid]

I Guess both

Key concept for Kenetic Therory... Same can be applied for liquids

• In a solid, the atoms are very attracted to one another. The atoms vibrate but stay in fixed positions because of their strong attractions for one another.
• Heating a solid increases the motion of the atoms.
• An increase in the motion of the atoms competes with the attraction between atoms and causes them to move a little further apart.
• Cooling a solid decreases the motion of the atoms.
• A decrease in the motion of the atoms allows the attractions between atoms to bring them a little close together.

Molecules or particles moving further away is expanding right

 

[Osaid Zahid]

shortwavelenght is the reason + and they have LESS ionization power. The atom would become ion if it had more proton and less electron, it needs to get stable by gaining electrons. the current itself is responsible of creating magnetic field

ok Silly me i need to revise more... i have almost forgotten radioactivity lol ..., ok and yes that is what i meant wont it be an ion since it has gained an extra proton ? and why does current do that i know it a property but then why electrons generate the field?

 

[Osaid Zahid]

this was the qstn i wrote wrong one

A liquid is heated.
Which statement is incorrect?
A The molecules expand.
B The molecules gain energy.
C The molecules move further apart.
D The molecules move faster.

Option A..... Molecules Themselves Dont Expand !

 

[Osaid Zahid]

when proton is gained, new element forms with equal number of electrons in an atom and the second question: i understood i guess so the current causes poles N and S to be made in solenoid which results in magnetic field being created

Yes you are onto the point the new element is stable ...... Were does it get that electron ..... and i wasn't particularly taking abt selenoind just a peice of Cu wire... The baic reason is the magnetic feild and the electric feild are both related and part of somting bigger the electromagentic field will do some more research after exams...