This question was asked in today's physics boards:
"Draw three equipotential surfaces corresponding to a field that uniformly increases in magnitude but remains constant along z - direction. How are these surfaces different from that of a constant electric field along the z - direction?"
WTF does this question mean??? And what is the answer
1wow...................................
I was confused and wrote d same answer but not completely........
I just draw a surface perpendicular to Z axis parallel to d XY plane and wrote that the two planes wud be of the same type on d Z axis(though didnt draw d other two ) hehehe..........
1hey i hav a doubt here...
dey'v asked equipotential surfaces...does it have 2 do anything wid d potential difference between 2 surfaces?
1No, i just wanted to show that Electric field is constant!!
if the p.d is const for same distance, then E. field will b constant
1I also marked the equipotential surfaces as V' , V'' and V'''
But i didnt write any thing else for this one like second part!!
1r1>r2 coz i wanted show that the elec. field will b diff
E= -∂V/∂r, Here r is a deciding factor...The mistake i made here is i shd also hav mentioned V'''-V''=V''-V'
11All parallel sufaces are equipotential surfaces.....so why shud r2 < r1??? r2 can also be > r1........or am i missing something here?
11deleted da.....sorry.....see, y shud the distance between the surfaces decrease??? After all, they are only surfaces where the potential is constant...
33In 1st fig also u should specify v2-v1=v1-v
waise baaki sab sahi hai
1ok...........next doubt......
OPtical and radio telescopoes are built on d ground while X RAY ASTRONOMY IS POSSIBLE ONLY FROM SATELLITES orniting d earth.Why d heck is it??????
And i wrote......
since X ray has a smaller wavelength than radio and visible waves so dere wud be more scattering (rayleigh wala) scattering ∞ 1/ λ4
so dey wud be scattered by d atmospheric particles while d oder two rays wont.......
Is this explanation ok????
1No anirudh, ∂V/∂r will be different for the two planes,if the potential difference between the two are same E= -∂V/∂r, Here r is a deciding factor...The mistake i made here is i shd also hav mentioned V'''-V''=V''-V' Thats If pd is same for the two, then numberator will b same, and Elec. field changes on changing r1 and r2....
we hav to show that the potential surfaces drawn shd b in accordance with the given condition( E increases)
1May b correct!!
What i wrote is
1. X rays hav high freq. so they are atennuated due to absorption of power by earth.-so no ground wave prop.
2. They are much higher in magnitude(But the condition for sky wave is that the freq. has to b less than the critical freaq.-usually around 5Ghz), and morever they are refracted to the space.
3.So the only possibility is through space wave propagation!!, as they r of high freq. -easily transmitted just like TV signals..
1dey hav HF so attenuation???? how???
i thought if u had low frequency u get attenuated.........wel thts we modulate signals wid HF carrier waves.....
11Akand, X-ray telescope ques: I wrote the same answer as u did........ massive tukka......CHEERS [4]
1No! power lost is directly propotional to frequescy
Or if u go by ur method scattering is prop. to 1/λ4,
therefore it is propotional to γ4.. so high freq. more easily scattered/waste of power!
1and guys .........for X ray frequency range...i hav written 1018 to 1022.........is it ok??
1i wrote 1017to 1019, i dont thing it is above 1020, that is 4 gamma rays.. just check ncert book, even i am not sure so i wrote some intermediate range...i know λ for X rays starts from 0.1 nm, so i calc. c/λ and got 3 x 1016
11For the x ray telescope question i wrote:
optical and radiowaves can penetrate the ionosphere (in the atmosphere) whereas x-rays, having much smaller wavelength, are absorbed by it.hence we can work with optical and radio telescope on earth's surface whereas x-ray telescope must be used on satellites orbiting above the earth atmosphere.
11Eureka, tune jo ans diya wo tho 2nd ques ki ans hai.....pehle ques ka answer????
I wrote an answer that will make Einstein forget physics........he'll just run around with his tongue stuck out and plucking his hair [3]
