1Whoever has physics exam (12th board) can refer to this thread which had been helpful 2 me..................
These are elementary doubts.....please do help.....
1.> Why is heavy water used as a moderator in a nuclear reactor?
I mean i kno it is used and i also kno y....but y heavy water..plzz explain..
2. What is the name given to that part of electromagnetic spectrum which is used for taking photographs of earth under foggy conditions from great heights?
3. What is the frequency of the output if 50Hz input is applied to a (a) H.W. rectifier (b) F.W. Rectifier
im confused....will d frequency becomes half in HW or double in FW??? (ITS VERY EASY)
4.Why is conductivity of electrolytes less than that of metals?
well i think less charge carriers in electrolytes whereas many electrons in metals..........is it rite???
-
UP 0 DOWN 0 0 30
30 Answers
62Read this.. only magnetic field wala part
http://en.wikipedia.org/wiki/Dipole
11yaa dude...........u r correct......wat i was sayin was rubbish..sorry bout tht
1can anyone explain why freq of full wave rectifier is half the original value and not double
1wah serious doubt........
Which two maxwell's equations led to prediction of em waves???
i think its faraday wala and ampere wala.....but im doubtfull.
1ok next...
Explain how d average temperature of the earth would have affected in the absence of atmosphere??
1ok one more logical and conceptual doubt..........
when we use a juction diode in a rectifier...and if we use our normal 220 volts(with max at 311) wont d diode just blast????????
I kno its AC but still.............wat is d maximum capacity of a diode???
1no dude................check for every half wave it repeats in FW.......so its frequency is 25 hz......... think carefully
113.
In the H.W the frequency will remain the same = 50 hz
While in a F.W the frequency will double = 100 hz
1If a coil is removed from a magnetic field (1) rapidly (2) slowly. In which case more work is done???
Nice question naa???
1ok forget d derivation.................. I am writing 12th std. CBSE tomorow not d final exam of Oxford univ in phy....hehe k anyways thnx bhaiyya
1ya it is analogous to elec field..............everything except sinθ....instead of cosθ we hav sinθ...........thnx bhaiyya......
15. Plot a graph to show how the following quantities vary with the frequency of the source. (a) Resistance (b) Capacitive reactance (c) Inductive reactance
please tell for resistance.....
1ok..........bt dipole of wat??? NORTH and SOUTH??? how can I take that?
62there is nothing much to be confused.
it works like a dipole of a electric charge...
The derivation and the working are almos tthe same :)
1ok next ques...
7. Derive an expr. for magnetic field intensity on d axis and eql. line of a MAGNET...
either im confused or its not in our syllabus or i may be too stupid 2day...
14th, metals have free electrons while , in electrolytes,there r ions...
electrons r light and easily carried awy by charge..., while, in case of ions, they r heavy and have less mobility...
another reason:size of electrons is very small.so they expirience less resistance and have more mobility, while, due to large size of ions, they expirience large resistance and have less mobility.
due to less mobility, they conduct effectively... i hope i m clear
3. IR
1ok thnx bhaiyya........................... but still... ions are more rite??? so wont conductivity inc.???
62in metal, charge carrier is small.. electron.
in electrolyte, they are ions.
Mobility is higher for electrons..
1bhaiyya...........name of d electromagnetic spectrum wave..........i think it shud be microwaves.....but cant say..
625. Plot a graph to show how the following quantities vary with the frequency of the source. (a) Resistance (b) Capacitive reactance (c) Inductive reactance
please tell for resistance.....
I dont see how resistance varies with frequency fo the source. I think it should be constant!
625. State Gauss theorem...........................WHICH one???? im confused
This is the electric flux one..'
Q/e= Flux = closed ∫E.dA
621.> Why is heavy water used as a moderator in a nuclear reactor?
I mean i kno it is used and i also kno y....but y heavy water..plzz explain..
This is something not very much in syllabus. It is used because water slows down the neutrons more than normal water. Heavy water slows it to a lesser extent.
Heavy water can work on normal uranium. Normal water can work only with enriched uranium!
2. What is the name given to that part of electromagnetic spectrum which is used for taking photographs of earth under foggy conditions from great heights?
They have longer wavelength
3. What is the frequency of the output if 50Hz input is applied to a (a) H.W. rectifier (b) F.W. Rectifier
im confused....will d frequency becomes half in HW or double in FW??? (ITS VERY EASY)
half wave weill have 50Hz
Full wave will have 25 HZ
draw it with graph and you will understand
|sinx| is full wave rectifier
2y = sinx + |sinx| is half wave rectifier
4.Why is conductivity of electrolytes less than that of metals?
well i think less charge carriers in electrolytes whereas many electrons in metals..........is it rite???
Charge carreier is small. In electrolyttes it is very large.. (My guess!)
16. Hw does d intensity of magnetisation of a PARAmagnetic material vary wid incresing applied magnetic field????
7. Why do magnetic lines of force prefer to pass through ferromagnetic substances than through air??
15. State Gauss theorem...........................WHICH one???? im confused